diff --git a/conftest.py b/conftest.py
index 4bf55b5f8e0..ba16c9be9db 100644
--- a/conftest.py
+++ b/conftest.py
@@ -18,7 +18,6 @@
 from yt.config import ytcfg
 from yt.utilities.answer_testing import utils
 
-
 # Global variables can be added to the pytest namespace
 answer_files = {}
 
diff --git a/scripts/iyt b/scripts/iyt
index 0c230574ca8..d00b60c7dd7 100755
--- a/scripts/iyt
+++ b/scripts/iyt
@@ -1,9 +1,14 @@
 #!python
 from __future__ import print_function
+
 import os
 import re
-from yt.mods import *
+
+from IPython.terminal.interactiveshell import TerminalInteractiveShell
+
 from yt.data_objects.data_containers import YTDataContainer
+from yt.mods import *
+
 namespace = locals().copy()
 namespace.pop("__builtins__", None)
 
@@ -24,7 +29,6 @@ except ImportError:
     code.interact(doc, None, namespace)
     sys.exit()
 
-from IPython.terminal.interactiveshell import TerminalInteractiveShell
 ip_shell = TerminalInteractiveShell(user_ns=namespace, banner1 = doc,
                                     display_banner = True)
 if "DISPLAY" in os.environ:
diff --git a/scripts/pr_backport.py b/scripts/pr_backport.py
index b3f521f5b11..0203c5beb35 100644
--- a/scripts/pr_backport.py
+++ b/scripts/pr_backport.py
@@ -1,8 +1,9 @@
+import shutil
+import tempfile
+
 import dateutil.parser
 import git
 import requests
-import shutil
-import tempfile
 
 API_URL = 'https://api.github.com/graphql'
 
diff --git a/setup.py b/setup.py
index cedd01cddc9..c2deeb6457c 100644
--- a/setup.py
+++ b/setup.py
@@ -1,21 +1,24 @@
+import glob
 import os
 import platform
-from concurrent.futures import ThreadPoolExecutor as Pool
-import glob
 import sys
+from concurrent.futures import ThreadPoolExecutor as Pool
+from distutils.ccompiler import CCompiler
+from distutils.version import LooseVersion
 from sys import platform as _platform
-from setuptools import setup, find_packages
-from setuptools.extension import Extension
+
+import pkg_resources
+from setuptools import find_packages, setup
 from setuptools.command.build_ext import build_ext as _build_ext
 from setuptools.command.sdist import sdist as _sdist
-from setupext import \
-    check_for_openmp, \
-    check_for_pyembree, \
-    read_embree_location, \
-    in_conda_env
-from distutils.version import LooseVersion
-from distutils.ccompiler import CCompiler
-import pkg_resources
+from setuptools.extension import Extension
+
+from setupext import (
+    check_for_openmp,
+    check_for_pyembree,
+    in_conda_env,
+    read_embree_location,
+)
 
 
 def _get_cpu_count():
diff --git a/setupext.py b/setupext.py
index 92c456babe0..0b66aaefa1c 100644
--- a/setupext.py
+++ b/setupext.py
@@ -5,14 +5,13 @@
 import subprocess
 import sys
 import tempfile
-
 from distutils import log
 from distutils.ccompiler import new_compiler
-from distutils.sysconfig import customize_compiler
 from distutils.errors import CompileError, LinkError
-from pkg_resources import resource_filename
-from subprocess import Popen, PIPE
+from distutils.sysconfig import customize_compiler
+from subprocess import PIPE, Popen
 
+from pkg_resources import resource_filename
 
 CCODE = """
 #include <omp.h>
diff --git a/tests/nose_runner.py b/tests/nose_runner.py
index 0ec1e0d52f2..681e170a465 100644
--- a/tests/nose_runner.py
+++ b/tests/nose_runner.py
@@ -1,18 +1,20 @@
-import sys
-import os
-import yaml
 import multiprocessing
-import nose
+import os
+import sys
+from io import StringIO
 
+import nose
+import numpy
+import yaml
 from coverage import Coverage
+
+from yt.config import ytcfg
+from yt.utilities.answer_testing.framework import AnswerTesting
+
 cov = Coverage(config_file=".coveragerc", branch=True, auto_data=True,
                concurrency="multiprocessing")
 cov.start()
 
-from io import StringIO
-from yt.config import ytcfg
-from yt.utilities.answer_testing.framework import AnswerTesting
-import numpy
 numpy.set_printoptions(threshold=5, edgeitems=1, precision=4)
 
 class NoseWorker(multiprocessing.Process):
diff --git a/tests/report_failed_answers.py b/tests/report_failed_answers.py
index 59ceab60bb3..5a3f9f45c1a 100644
--- a/tests/report_failed_answers.py
+++ b/tests/report_failed_answers.py
@@ -21,6 +21,7 @@
 import nose
 import numpy
 import requests
+
 from yt.config import ytcfg
 from yt.utilities.answer_testing.framework import AnswerTesting
 from yt.utilities.command_line import FileStreamer
diff --git a/yt/analysis_modules/absorption_spectrum/api.py b/yt/analysis_modules/absorption_spectrum/api.py
index bb66b6f4b45..fef030c4a9d 100644
--- a/yt/analysis_modules/absorption_spectrum/api.py
+++ b/yt/analysis_modules/absorption_spectrum/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "AbsorptionSpectrum",
diff --git a/yt/analysis_modules/cosmological_observation/api.py b/yt/analysis_modules/cosmological_observation/api.py
index da1df1ec4b7..6aef8c09554 100644
--- a/yt/analysis_modules/cosmological_observation/api.py
+++ b/yt/analysis_modules/cosmological_observation/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "CosmologySplice and LightCone",
diff --git a/yt/analysis_modules/halo_analysis/api.py b/yt/analysis_modules/halo_analysis/api.py
index e9eb1f054ad..d9bda9bf991 100644
--- a/yt/analysis_modules/halo_analysis/api.py
+++ b/yt/analysis_modules/halo_analysis/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "halo_analysis",
diff --git a/yt/analysis_modules/halo_finding/api.py b/yt/analysis_modules/halo_finding/api.py
index c0db4ee5e0c..04ea8fe0f8a 100644
--- a/yt/analysis_modules/halo_finding/api.py
+++ b/yt/analysis_modules/halo_finding/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "halo_finding",
diff --git a/yt/analysis_modules/halo_mass_function/api.py b/yt/analysis_modules/halo_mass_function/api.py
index b978be38cc8..7b885c34a6e 100644
--- a/yt/analysis_modules/halo_mass_function/api.py
+++ b/yt/analysis_modules/halo_mass_function/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "halo_mass_function",
diff --git a/yt/analysis_modules/photon_simulator/api.py b/yt/analysis_modules/photon_simulator/api.py
index ed738750d0e..b5be89bdd4a 100644
--- a/yt/analysis_modules/photon_simulator/api.py
+++ b/yt/analysis_modules/photon_simulator/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "photon_simulator",
diff --git a/yt/analysis_modules/ppv_cube/api.py b/yt/analysis_modules/ppv_cube/api.py
index 26012b96fcb..3c5510cd900 100644
--- a/yt/analysis_modules/ppv_cube/api.py
+++ b/yt/analysis_modules/ppv_cube/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "PPVCube",
diff --git a/yt/analysis_modules/radmc3d_export/api.py b/yt/analysis_modules/radmc3d_export/api.py
index e1d0478f3ea..a0841e1cf5c 100644
--- a/yt/analysis_modules/radmc3d_export/api.py
+++ b/yt/analysis_modules/radmc3d_export/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "radmc3d_export",
diff --git a/yt/analysis_modules/star_analysis/api.py b/yt/analysis_modules/star_analysis/api.py
index bc4d7cf5dff..c9a6f8fa523 100644
--- a/yt/analysis_modules/star_analysis/api.py
+++ b/yt/analysis_modules/star_analysis/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "star_analysis",
diff --git a/yt/analysis_modules/sunrise_export/api.py b/yt/analysis_modules/sunrise_export/api.py
index 2e69ffab1c3..bdac8165aad 100644
--- a/yt/analysis_modules/sunrise_export/api.py
+++ b/yt/analysis_modules/sunrise_export/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "sunrise_export",
diff --git a/yt/analysis_modules/sunyaev_zeldovich/api.py b/yt/analysis_modules/sunyaev_zeldovich/api.py
index e32ec19a91b..eef2607fa49 100644
--- a/yt/analysis_modules/sunyaev_zeldovich/api.py
+++ b/yt/analysis_modules/sunyaev_zeldovich/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "sunyaev_zeldovich",
diff --git a/yt/analysis_modules/two_point_functions/api.py b/yt/analysis_modules/two_point_functions/api.py
index 6346eb057a6..8d8ee99a90d 100644
--- a/yt/analysis_modules/two_point_functions/api.py
+++ b/yt/analysis_modules/two_point_functions/api.py
@@ -1,5 +1,4 @@
-from yt.utilities.exceptions import \
-    YTModuleRemoved
+from yt.utilities.exceptions import YTModuleRemoved
 
 raise YTModuleRemoved(
     "two_point_functions",
diff --git a/yt/api.py b/yt/api.py
index d9ec8215162..5ac3ae5ca86 100644
--- a/yt/api.py
+++ b/yt/api.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/config.py b/yt/config.py
index 4657478749f..52a7a727caf 100644
--- a/yt/config.py
+++ b/yt/config.py
@@ -1,6 +1,6 @@
+import configparser
 import os
 import warnings
-import configparser
 
 ytcfg_defaults = dict(
     serialize = 'False',
diff --git a/yt/convenience.py b/yt/convenience.py
index 2b5423905ed..c1f6038b32e 100644
--- a/yt/convenience.py
+++ b/yt/convenience.py
@@ -3,14 +3,14 @@
 # Named imports
 from yt.config import ytcfg
 from yt.funcs import mylog
-from yt.utilities.parameter_file_storage import \
-    output_type_registry, \
-    simulation_time_series_registry, \
-    EnzoRunDatabase
-from yt.utilities.exceptions import \
-    YTOutputNotIdentified, \
-    YTSimulationNotIdentified
+from yt.utilities.exceptions import YTOutputNotIdentified, YTSimulationNotIdentified
 from yt.utilities.hierarchy_inspection import find_lowest_subclasses
+from yt.utilities.parameter_file_storage import (
+    EnzoRunDatabase,
+    output_type_registry,
+    simulation_time_series_registry,
+)
+
 
 def _sanitize_load_args(*args):
     """Filter out non-pathlike arguments, ensure list form, and expand '~' tokens"""
diff --git a/yt/data_objects/api.py b/yt/data_objects/api.py
index 003137181b6..4dca4a02880 100644
--- a/yt/data_objects/api.py
+++ b/yt/data_objects/api.py
@@ -1,35 +1,10 @@
-from .grid_patch import \
-    AMRGridPatch
-
-from .octree_subset import \
-    OctreeSubset
-
-from .static_output import \
-    Dataset
-
-from .profiles import \
-    create_profile, \
-    Profile1D, \
-    Profile2D, \
-    Profile3D, \
-    ParticleProfile
-
-from .time_series import \
-    DatasetSeries, \
-    DatasetSeriesObject
-
-from .analyzer_objects import \
-    AnalysisTask, analysis_task
-
-from .data_containers import \
-    data_object_registry
-
-from . import construction_data_containers as __cdc
-from . import selection_data_containers as __sdc
-
-from .image_array import \
-    ImageArray
-
-from .particle_filters import \
-    particle_filter, \
-    add_particle_filter
+from . import construction_data_containers as __cdc, selection_data_containers as __sdc
+from .analyzer_objects import AnalysisTask, analysis_task
+from .data_containers import data_object_registry
+from .grid_patch import AMRGridPatch
+from .image_array import ImageArray
+from .octree_subset import OctreeSubset
+from .particle_filters import add_particle_filter, particle_filter
+from .profiles import ParticleProfile, Profile1D, Profile2D, Profile3D, create_profile
+from .static_output import Dataset
+from .time_series import DatasetSeries, DatasetSeriesObject
diff --git a/yt/data_objects/construction_data_containers.py b/yt/data_objects/construction_data_containers.py
index a4eeec752cb..7073b22395b 100644
--- a/yt/data_objects/construction_data_containers.py
+++ b/yt/data_objects/construction_data_containers.py
@@ -1,62 +1,55 @@
-import numpy as np
-from functools import wraps
 import fileinput
 import io
-from re import finditer
-from tempfile import NamedTemporaryFile, TemporaryFile
 import os
 import sys
 import zipfile
+from functools import wraps
+from re import finditer
+from tempfile import NamedTemporaryFile, TemporaryFile
+
+import numpy as np
 
-from yt.config import ytcfg
-from yt.data_objects.data_containers import \
-    YTSelectionContainer1D, \
-    YTSelectionContainer2D, \
-    YTSelectionContainer3D
-from yt.data_objects.field_data import \
-    YTFieldData
-from yt.funcs import \
-    ensure_list, \
-    mylog, \
-    get_memory_usage, \
-    iterable, \
-    only_on_root
-from yt.utilities.exceptions import \
-    YTParticleDepositionNotImplemented, \
-    YTNoAPIKey, \
-    YTTooManyVertices
-from yt.fields.field_exceptions import \
-    NeedsGridType
-from yt.utilities.lib.quad_tree import \
-    QuadTree
-from yt.utilities.lib.interpolators import \
-    ghost_zone_interpolate
-from yt.utilities.lib.misc_utilities import \
-    fill_region, fill_region_float
-from yt.utilities.lib.marching_cubes import \
-    march_cubes_grid, march_cubes_grid_flux
-from yt.utilities.minimal_representation import \
-    MinimalProjectionData
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_objects, parallel_root_only, communication_system
-from yt.units.unit_object import Unit
-from yt.units.yt_array import uconcatenate
 import yt.geometry.particle_deposit as particle_deposit
+from yt.config import ytcfg
+from yt.data_objects.data_containers import (
+    YTSelectionContainer1D,
+    YTSelectionContainer2D,
+    YTSelectionContainer3D,
+)
+from yt.data_objects.field_data import YTFieldData
+from yt.extern.tqdm import tqdm
+from yt.fields.field_exceptions import NeedsGridType, NeedsOriginalGrid
+from yt.frontends.sph.data_structures import ParticleDataset
+from yt.frontends.stream.api import load_uniform_grid
+from yt.funcs import ensure_list, get_memory_usage, iterable, mylog, only_on_root
 from yt.geometry.coordinates.cartesian_coordinates import all_data
+from yt.units.unit_object import Unit
+from yt.units.yt_array import YTArray, uconcatenate
+from yt.utilities.exceptions import (
+    YTNoAPIKey,
+    YTParticleDepositionNotImplemented,
+    YTTooManyVertices,
+)
 from yt.utilities.grid_data_format.writer import write_to_gdf
-from yt.fields.field_exceptions import \
-    NeedsOriginalGrid
-from yt.frontends.stream.api import load_uniform_grid
-from yt.frontends.sph.data_structures import ParticleDataset
-from yt.units.yt_array import YTArray
-from yt.utilities.lib.pixelization_routines import \
-    pixelize_sph_kernel_arbitrary_grid, \
-    interpolate_sph_grid_gather, \
-    interpolate_sph_positions_gather, \
-    normalization_3d_utility, \
-    normalization_1d_utility
-from yt.extern.tqdm import tqdm
 from yt.utilities.lib.cyoctree import CyOctree
+from yt.utilities.lib.interpolators import ghost_zone_interpolate
+from yt.utilities.lib.marching_cubes import march_cubes_grid, march_cubes_grid_flux
+from yt.utilities.lib.misc_utilities import fill_region, fill_region_float
+from yt.utilities.lib.pixelization_routines import (
+    interpolate_sph_grid_gather,
+    interpolate_sph_positions_gather,
+    normalization_1d_utility,
+    normalization_3d_utility,
+    pixelize_sph_kernel_arbitrary_grid,
+)
+from yt.utilities.lib.quad_tree import QuadTree
+from yt.utilities.minimal_representation import MinimalProjectionData
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    communication_system,
+    parallel_objects,
+    parallel_root_only,
+)
+
 
 class YTStreamline(YTSelectionContainer1D):
     """
diff --git a/yt/data_objects/data_containers.py b/yt/data_objects/data_containers.py
index ecf2f78934e..0baffffef05 100644
--- a/yt/data_objects/data_containers.py
+++ b/yt/data_objects/data_containers.py
@@ -1,62 +1,54 @@
 import itertools
-import uuid
-
 import os
-import numpy as np
-import weakref
 import shelve
-
+import uuid
+import weakref
 from collections import defaultdict
 from contextlib import contextmanager
 
-from yt.fields.derived_field import \
-    DerivedField
-from yt.frontends.ytdata.utilities import \
-    save_as_dataset
-from yt.funcs import \
-    get_output_filename, \
-    mylog, \
-    ensure_list, \
-    fix_axis, \
-    iterable, \
-    validate_width_tuple
-from yt.units.yt_array import \
-    YTArray, \
-    YTQuantity
-import yt.units.dimensions as ytdims
-from unyt.exceptions import \
-    UnitConversionError, \
-    UnitParseError
-from yt.utilities.exceptions import \
-    YTFieldUnitError, \
-    YTFieldUnitParseError, \
-    YTSpatialFieldUnitError, \
-    YTCouldNotGenerateField, \
-    YTFieldNotParseable, \
-    YTFieldNotFound, \
-    YTFieldTypeNotFound, \
-    YTDataSelectorNotImplemented, \
-    YTDimensionalityError, \
-    YTNonIndexedDataContainer, \
-    YTBooleanObjectError, \
-    YTBooleanObjectsWrongDataset, YTException
-from yt.utilities.lib.marching_cubes import \
-    march_cubes_grid, march_cubes_grid_flux
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    ParallelAnalysisInterface
-from yt.utilities.parameter_file_storage import \
-    ParameterFileStore
-from yt.utilities.amr_kdtree.api import \
-    AMRKDTree
-from .derived_quantities import DerivedQuantityCollection
-from yt.fields.field_exceptions import \
-    NeedsGridType
+import numpy as np
+from unyt.exceptions import UnitConversionError, UnitParseError
+
 import yt.geometry.selection_routines
-from yt.geometry.selection_routines import \
-    compose_selector
-from yt.units.yt_array import uconcatenate
+import yt.units.dimensions as ytdims
 from yt.data_objects.field_data import YTFieldData
 from yt.data_objects.profiles import create_profile
+from yt.fields.derived_field import DerivedField
+from yt.fields.field_exceptions import NeedsGridType
+from yt.frontends.ytdata.utilities import save_as_dataset
+from yt.funcs import (
+    ensure_list,
+    fix_axis,
+    get_output_filename,
+    iterable,
+    mylog,
+    validate_width_tuple,
+)
+from yt.geometry.selection_routines import compose_selector
+from yt.units.yt_array import YTArray, YTQuantity, uconcatenate
+from yt.utilities.amr_kdtree.api import AMRKDTree
+from yt.utilities.exceptions import (
+    YTBooleanObjectError,
+    YTBooleanObjectsWrongDataset,
+    YTCouldNotGenerateField,
+    YTDataSelectorNotImplemented,
+    YTDimensionalityError,
+    YTException,
+    YTFieldNotFound,
+    YTFieldNotParseable,
+    YTFieldTypeNotFound,
+    YTFieldUnitError,
+    YTFieldUnitParseError,
+    YTNonIndexedDataContainer,
+    YTSpatialFieldUnitError,
+)
+from yt.utilities.lib.marching_cubes import march_cubes_grid, march_cubes_grid_flux
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    ParallelAnalysisInterface,
+)
+from yt.utilities.parameter_file_storage import ParameterFileStore
+
+from .derived_quantities import DerivedQuantityCollection
 
 data_object_registry = {}
 
diff --git a/yt/data_objects/derived_quantities.py b/yt/data_objects/derived_quantities.py
index 5b90ecbbe50..b88814559c7 100644
--- a/yt/data_objects/derived_quantities.py
+++ b/yt/data_objects/derived_quantities.py
@@ -1,16 +1,14 @@
 import numpy as np
 
-from yt.funcs import \
-    camelcase_to_underscore, \
-    ensure_list
+from yt.funcs import camelcase_to_underscore, ensure_list
 from yt.units.yt_array import array_like_field
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    ParallelAnalysisInterface, parallel_objects
-from yt.utilities.physical_constants import \
-    gravitational_constant_cgs
+from yt.utilities.exceptions import YTParticleTypeNotFound
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    ParallelAnalysisInterface,
+    parallel_objects,
+)
+from yt.utilities.physical_constants import gravitational_constant_cgs
 from yt.utilities.physical_ratios import HUGE
-from yt.utilities.exceptions import \
-    YTParticleTypeNotFound
 
 derived_quantity_registry = {}
 
diff --git a/yt/data_objects/grid_patch.py b/yt/data_objects/grid_patch.py
index 7dd1e7d6719..55de59a3139 100644
--- a/yt/data_objects/grid_patch.py
+++ b/yt/data_objects/grid_patch.py
@@ -1,23 +1,21 @@
 import warnings
 import weakref
+
 import numpy as np
 
+import yt.geometry.particle_deposit as particle_deposit
 from yt.config import ytcfg
-from yt.data_objects.data_containers import \
-    YTSelectionContainer
+from yt.data_objects.data_containers import YTSelectionContainer
 from yt.funcs import iterable
 from yt.geometry.selection_routines import convert_mask_to_indices
-import yt.geometry.particle_deposit as particle_deposit
 from yt.units.yt_array import YTArray
-from yt.utilities.exceptions import \
-    YTFieldTypeNotFound, \
-    YTParticleDepositionNotImplemented
-from yt.utilities.lib.interpolators import \
-    ghost_zone_interpolate
-from yt.utilities.lib.mesh_utilities import \
-    clamp_edges
-from yt.utilities.nodal_data_utils import \
-    get_nodal_slices
+from yt.utilities.exceptions import (
+    YTFieldTypeNotFound,
+    YTParticleDepositionNotImplemented,
+)
+from yt.utilities.lib.interpolators import ghost_zone_interpolate
+from yt.utilities.lib.mesh_utilities import clamp_edges
+from yt.utilities.nodal_data_utils import get_nodal_slices
 
 RECONSTRUCT_INDEX = bool(ytcfg.get('yt', 'reconstruct_index'))
 
diff --git a/yt/data_objects/image_array.py b/yt/data_objects/image_array.py
index 02c33ecbf3f..5fdaa88149f 100644
--- a/yt/data_objects/image_array.py
+++ b/yt/data_objects/image_array.py
@@ -1,9 +1,10 @@
 import warnings
+
 import numpy as np
-from yt.config import \
-    ytcfg
-from yt.visualization.image_writer import write_bitmap, write_image
+
+from yt.config import ytcfg
 from yt.units.yt_array import YTArray
+from yt.visualization.image_writer import write_bitmap, write_image
 
 
 class ImageArray(YTArray):
diff --git a/yt/data_objects/level_sets/api.py b/yt/data_objects/level_sets/api.py
index c14ab973caf..609885e52cb 100644
--- a/yt/data_objects/level_sets/api.py
+++ b/yt/data_objects/level_sets/api.py
@@ -1,20 +1,11 @@
-from .contour_finder import \
-    identify_contours
-
-from .clump_handling import \
-    Clump, \
-    find_clumps, \
-    get_lowest_clumps
-
-from .clump_info_items import \
-    add_clump_info
-
-from .clump_validators import \
-    add_validator
-    
-from .clump_tools import \
-    recursive_all_clumps, \
-    return_all_clumps, \
-    return_bottom_clumps, \
-    recursive_bottom_clumps, \
-    clump_list_sort
+from .clump_handling import Clump, find_clumps, get_lowest_clumps
+from .clump_info_items import add_clump_info
+from .clump_tools import (
+    clump_list_sort,
+    recursive_all_clumps,
+    recursive_bottom_clumps,
+    return_all_clumps,
+    return_bottom_clumps,
+)
+from .clump_validators import add_validator
+from .contour_finder import identify_contours
diff --git a/yt/data_objects/level_sets/clump_handling.py b/yt/data_objects/level_sets/clump_handling.py
index 920ee1c5d62..b2c01ba3701 100644
--- a/yt/data_objects/level_sets/clump_handling.py
+++ b/yt/data_objects/level_sets/clump_handling.py
@@ -1,23 +1,16 @@
-import numpy as np
 import uuid
 
-from yt.fields.derived_field import \
-    ValidateSpatial
-from yt.frontends.ytdata.utilities import \
-    save_as_dataset
-from yt.funcs import \
-    issue_deprecation_warning, \
-    get_output_filename, \
-    mylog
-from yt.utilities.tree_container import \
-    TreeContainer
-
-from .clump_info_items import \
-    clump_info_registry
-from .clump_validators import \
-    clump_validator_registry
-from .contour_finder import \
-    identify_contours
+import numpy as np
+
+from yt.fields.derived_field import ValidateSpatial
+from yt.frontends.ytdata.utilities import save_as_dataset
+from yt.funcs import get_output_filename, issue_deprecation_warning, mylog
+from yt.utilities.tree_container import TreeContainer
+
+from .clump_info_items import clump_info_registry
+from .clump_validators import clump_validator_registry
+from .contour_finder import identify_contours
+
 
 def add_contour_field(ds, contour_key):
     def _contours(field, data):
diff --git a/yt/data_objects/level_sets/clump_info_items.py b/yt/data_objects/level_sets/clump_info_items.py
index f0636b96fd5..d5631c9c8e0 100644
--- a/yt/data_objects/level_sets/clump_info_items.py
+++ b/yt/data_objects/level_sets/clump_info_items.py
@@ -1,7 +1,6 @@
 import numpy as np
 
-from yt.utilities.operator_registry import \
-     OperatorRegistry
+from yt.utilities.operator_registry import OperatorRegistry
 
 clump_info_registry = OperatorRegistry()
 
diff --git a/yt/data_objects/level_sets/clump_tools.py b/yt/data_objects/level_sets/clump_tools.py
index e037d35f1c9..d1d4ec446d9 100644
--- a/yt/data_objects/level_sets/clump_tools.py
+++ b/yt/data_objects/level_sets/clump_tools.py
@@ -1,4 +1,5 @@
 import numpy as np
+
 nar = np.array
 
 counter = 0
diff --git a/yt/data_objects/level_sets/clump_validators.py b/yt/data_objects/level_sets/clump_validators.py
index b57be4ef69c..3cb9a1d17d1 100644
--- a/yt/data_objects/level_sets/clump_validators.py
+++ b/yt/data_objects/level_sets/clump_validators.py
@@ -1,11 +1,8 @@
 import numpy as np
 
-from yt.utilities.lib.misc_utilities import \
-    gravitational_binding_energy
-from yt.utilities.operator_registry import \
-    OperatorRegistry
-from yt.utilities.physical_constants import \
-    gravitational_constant_cgs as G
+from yt.utilities.lib.misc_utilities import gravitational_binding_energy
+from yt.utilities.operator_registry import OperatorRegistry
+from yt.utilities.physical_constants import gravitational_constant_cgs as G
 
 clump_validator_registry = OperatorRegistry()
 
diff --git a/yt/data_objects/level_sets/contour_finder.py b/yt/data_objects/level_sets/contour_finder.py
index b05bc12f8a1..31ebd6d8ae5 100644
--- a/yt/data_objects/level_sets/contour_finder.py
+++ b/yt/data_objects/level_sets/contour_finder.py
@@ -1,13 +1,16 @@
+from collections import defaultdict
+
 import numpy as np
 
-from collections import defaultdict
+from yt.funcs import get_pbar, mylog
+from yt.utilities.lib.contour_finding import (
+    ContourTree,
+    TileContourTree,
+    link_node_contours,
+    update_joins,
+)
+from yt.utilities.lib.partitioned_grid import PartitionedGrid
 
-from yt.funcs import mylog, get_pbar
-from yt.utilities.lib.contour_finding import \
-    ContourTree, TileContourTree, link_node_contours, \
-    update_joins
-from yt.utilities.lib.partitioned_grid import \
-    PartitionedGrid
 
 def identify_contours(data_source, field, min_val, max_val,
                           cached_fields=None):
diff --git a/yt/data_objects/level_sets/tests/test_clump_finding.py b/yt/data_objects/level_sets/tests/test_clump_finding.py
index b0a77b2e0b1..f58c04f4e32 100644
--- a/yt/data_objects/level_sets/tests/test_clump_finding.py
+++ b/yt/data_objects/level_sets/tests/test_clump_finding.py
@@ -1,26 +1,17 @@
-import numpy as np
 import os
 import shutil
 import tempfile
 
+import numpy as np
 
-from yt.data_objects.level_sets.api import \
-    add_clump_info, \
-    Clump, \
-    find_clumps
+from yt.convenience import load
+from yt.data_objects.level_sets.api import Clump, add_clump_info, find_clumps
 from yt.data_objects.level_sets.clump_info_items import clump_info_registry
-from yt.convenience import \
-    load
-from yt.fields.derived_field import \
-    ValidateParameter
-from yt.frontends.stream.api import \
-    load_uniform_grid
-from yt.testing import \
-    assert_array_equal, \
-    assert_equal, \
-    requires_file
-from yt.utilities.answer_testing.framework import \
-    data_dir_load
+from yt.fields.derived_field import ValidateParameter
+from yt.frontends.stream.api import load_uniform_grid
+from yt.testing import assert_array_equal, assert_equal, requires_file
+from yt.utilities.answer_testing.framework import data_dir_load
+
 
 def test_clump_finding():
     n_c = 8
diff --git a/yt/data_objects/octree_subset.py b/yt/data_objects/octree_subset.py
index d1a119b13f5..159c1e27a15 100644
--- a/yt/data_objects/octree_subset.py
+++ b/yt/data_objects/octree_subset.py
@@ -1,21 +1,21 @@
 from contextlib import contextmanager
+
 import numpy as np
 
-from yt.data_objects.data_containers import \
-    YTSelectionContainer
 import yt.geometry.particle_deposit as particle_deposit
 import yt.geometry.particle_smooth as particle_smooth
-
+from yt.data_objects.data_containers import YTSelectionContainer
 from yt.funcs import mylog
-from yt.utilities.lib.geometry_utils import compute_morton
-from yt.geometry.particle_oct_container import \
-    ParticleOctreeContainer
-from yt.units.yt_array import YTArray
+from yt.geometry.particle_oct_container import ParticleOctreeContainer
 from yt.units.dimensions import length
-from yt.utilities.exceptions import \
-    YTInvalidPositionArray, \
-    YTFieldTypeNotFound, \
-    YTParticleDepositionNotImplemented
+from yt.units.yt_array import YTArray
+from yt.utilities.exceptions import (
+    YTFieldTypeNotFound,
+    YTInvalidPositionArray,
+    YTParticleDepositionNotImplemented,
+)
+from yt.utilities.lib.geometry_utils import compute_morton
+
 
 def cell_count_cache(func):
     def cc_cache_func(self, dobj):
diff --git a/yt/data_objects/particle_container.py b/yt/data_objects/particle_container.py
index e4c06662ef2..0541b18c6d6 100644
--- a/yt/data_objects/particle_container.py
+++ b/yt/data_objects/particle_container.py
@@ -1,13 +1,12 @@
 import contextlib
 
-from yt.data_objects.data_containers import \
-    YTFieldData, \
-    YTSelectionContainer
-from yt.funcs import \
-    ensure_list
-from yt.utilities.exceptions import \
-    YTNonIndexedDataContainer, \
-    YTDataSelectorNotImplemented
+from yt.data_objects.data_containers import YTFieldData, YTSelectionContainer
+from yt.funcs import ensure_list
+from yt.utilities.exceptions import (
+    YTDataSelectorNotImplemented,
+    YTNonIndexedDataContainer,
+)
+
 
 def _non_indexed(name):
     def _func_non_indexed(self, *args, **kwargs):
diff --git a/yt/data_objects/particle_filters.py b/yt/data_objects/particle_filters.py
index 9e2e8ba3016..ba70994f5a7 100644
--- a/yt/data_objects/particle_filters.py
+++ b/yt/data_objects/particle_filters.py
@@ -1,8 +1,7 @@
 import copy
 from contextlib import contextmanager
 
-from yt.fields.field_info_container import \
-    NullFunc, TranslationFunc
+from yt.fields.field_info_container import NullFunc, TranslationFunc
 from yt.funcs import mylog
 from yt.utilities.exceptions import YTIllDefinedFilter
 
diff --git a/yt/data_objects/particle_trajectories.py b/yt/data_objects/particle_trajectories.py
index 94e83b21c2a..6c7a1a21f28 100644
--- a/yt/data_objects/particle_trajectories.py
+++ b/yt/data_objects/particle_trajectories.py
@@ -1,15 +1,16 @@
-from yt.data_objects.field_data import YTFieldData
-from yt.utilities.lib.particle_mesh_operations import CICSample_3
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_root_only
-from yt.funcs import mylog, get_pbar
-from yt.units.yt_array import array_like_field
-from yt.config import ytcfg
-from yt.utilities.exceptions import YTIllDefinedParticleData
 from collections import OrderedDict
 
 import numpy as np
+
+from yt.config import ytcfg
+from yt.data_objects.field_data import YTFieldData
+from yt.funcs import get_pbar, mylog
+from yt.units.yt_array import array_like_field
+from yt.utilities.exceptions import YTIllDefinedParticleData
+from yt.utilities.lib.particle_mesh_operations import CICSample_3
 from yt.utilities.on_demand_imports import _h5py as h5py
+from yt.utilities.parallel_tools.parallel_analysis_interface import parallel_root_only
+
 
 class ParticleTrajectories:
     r"""A collection of particle trajectories in time over a series of
diff --git a/yt/data_objects/particle_unions.py b/yt/data_objects/particle_unions.py
index 1d1e0ca9964..770f11a8e32 100644
--- a/yt/data_objects/particle_unions.py
+++ b/yt/data_objects/particle_unions.py
@@ -1,5 +1,6 @@
 from .unions import Union
 
+
 class ParticleUnion(Union):
     _union_type = "particle"
     def __init__(self, name, sub_types):
diff --git a/yt/data_objects/profiles.py b/yt/data_objects/profiles.py
index 063f6ef5c78..7a4fa7139ef 100644
--- a/yt/data_objects/profiles.py
+++ b/yt/data_objects/profiles.py
@@ -1,32 +1,32 @@
 import numpy as np
 
+from yt.data_objects.field_data import YTFieldData
 from yt.fields.derived_field import DerivedField
-from yt.frontends.ytdata.utilities import \
-    save_as_dataset
-from yt.funcs import \
-    get_output_filename, \
-    ensure_list, \
-    iterable, \
-    issue_deprecation_warning, \
-    mylog
-from yt.units.yt_array import \
-    array_like_field, \
-    YTQuantity
+from yt.frontends.ytdata.utilities import save_as_dataset
+from yt.funcs import (
+    ensure_list,
+    get_output_filename,
+    issue_deprecation_warning,
+    iterable,
+    mylog,
+)
 from yt.units.unit_object import Unit
-from yt.data_objects.field_data import YTFieldData
-from yt.utilities.exceptions import \
-    YTIllDefinedProfile, \
-    YTIllDefinedBounds, \
-    YTProfileDataShape
-from yt.utilities.lib.misc_utilities import \
-    new_bin_profile1d, \
-    new_bin_profile2d, \
-    new_bin_profile3d
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    ParallelAnalysisInterface, parallel_objects
-from yt.utilities.lib.particle_mesh_operations import \
-    CICDeposit_2, \
-    NGPDeposit_2
+from yt.units.yt_array import YTQuantity, array_like_field
+from yt.utilities.exceptions import (
+    YTIllDefinedBounds,
+    YTIllDefinedProfile,
+    YTProfileDataShape,
+)
+from yt.utilities.lib.misc_utilities import (
+    new_bin_profile1d,
+    new_bin_profile2d,
+    new_bin_profile3d,
+)
+from yt.utilities.lib.particle_mesh_operations import CICDeposit_2, NGPDeposit_2
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    ParallelAnalysisInterface,
+    parallel_objects,
+)
 
 
 def _sanitize_min_max_units(amin, amax, finfo, registry):
diff --git a/yt/data_objects/region_expression.py b/yt/data_objects/region_expression.py
index 8ea527c8025..67ba3987b15 100644
--- a/yt/data_objects/region_expression.py
+++ b/yt/data_objects/region_expression.py
@@ -4,8 +4,10 @@
 from yt.units.yt_array import YTQuantity
 from yt.utilities.exceptions import YTDimensionalityError
 from yt.visualization.line_plot import LineBuffer
+
 from .data_containers import _get_ipython_key_completion
 
+
 class RegionExpression:
     _all_data = None
     def __init__(self, ds):
diff --git a/yt/data_objects/selection_data_containers.py b/yt/data_objects/selection_data_containers.py
index 8a5c743feed..44f6e6b64d2 100644
--- a/yt/data_objects/selection_data_containers.py
+++ b/yt/data_objects/selection_data_containers.py
@@ -1,42 +1,41 @@
 import numpy as np
 
-from yt.data_objects.data_containers import \
-    YTSelectionContainer0D, YTSelectionContainer1D, \
-    YTSelectionContainer2D, YTSelectionContainer3D, YTSelectionContainer
+from yt.data_objects.data_containers import (
+    YTSelectionContainer,
+    YTSelectionContainer0D,
+    YTSelectionContainer1D,
+    YTSelectionContainer2D,
+    YTSelectionContainer3D,
+)
 from yt.data_objects.static_output import Dataset
-from yt.frontends.sph.data_structures import \
-    SPHDataset
-from yt.funcs import \
-    ensure_list, \
-    iterable, \
-    validate_width_tuple, \
-    fix_length, \
-    fix_axis, \
-    mylog, \
-    validate_3d_array, \
-    validate_float, \
-    validate_iterable, \
-    validate_object, \
-    validate_axis, \
-    validate_center
-from yt.units.yt_array import \
-    udot, \
-    unorm, \
-    YTArray, \
-    YTQuantity
-from yt.utilities.exceptions import \
-    YTSphereTooSmall, \
-    YTIllDefinedCutRegion, \
-    YTEllipsoidOrdering, \
-    YTException
-from yt.utilities.lib.pixelization_routines import \
-    SPHKernelInterpolationTable
-from yt.utilities.minimal_representation import \
-    MinimalSliceData
+from yt.frontends.sph.data_structures import SPHDataset
+from yt.funcs import (
+    ensure_list,
+    fix_axis,
+    fix_length,
+    iterable,
+    mylog,
+    validate_3d_array,
+    validate_axis,
+    validate_center,
+    validate_float,
+    validate_iterable,
+    validate_object,
+    validate_width_tuple,
+)
+from yt.geometry.selection_routines import points_in_cells
+from yt.units.yt_array import YTArray, YTQuantity, udot, unorm
+from yt.utilities.exceptions import (
+    YTEllipsoidOrdering,
+    YTException,
+    YTIllDefinedCutRegion,
+    YTSphereTooSmall,
+)
+from yt.utilities.lib.pixelization_routines import SPHKernelInterpolationTable
 from yt.utilities.math_utils import get_rotation_matrix
+from yt.utilities.minimal_representation import MinimalSliceData
+from yt.utilities.on_demand_imports import _miniball, _scipy
 from yt.utilities.orientation import Orientation
-from yt.geometry.selection_routines import points_in_cells
-from yt.utilities.on_demand_imports import _scipy, _miniball
 
 
 class YTPoint(YTSelectionContainer0D):
diff --git a/yt/data_objects/static_output.py b/yt/data_objects/static_output.py
index 9a74767393c..1e90612ffcc 100644
--- a/yt/data_objects/static_output.py
+++ b/yt/data_objects/static_output.py
@@ -1,76 +1,62 @@
 import functools
 import itertools
-import numpy as np
 import os
-from stat import ST_CTIME
+import pickle
 import time
-import weakref
 import warnings
-
+import weakref
 from collections import defaultdict
-import pickle
+from stat import ST_CTIME
+
+import numpy as np
 
 from yt.config import ytcfg
-from yt.fields.derived_field import \
-    DerivedField
-from yt.fields.field_type_container import \
-    FieldTypeContainer
-from yt.funcs import \
-    mylog, \
-    set_intersection, \
-    ensure_list, \
-    issue_deprecation_warning, \
-    iterable, \
-    setdefaultattr
-from yt.utilities.cosmology import \
-    Cosmology
-from yt.utilities.exceptions import \
-    YTObjectNotImplemented, \
-    YTFieldNotFound, \
-    YTGeometryNotSupported, \
-    YTIllDefinedParticleFilter
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_root_only
-from yt.utilities.parameter_file_storage import \
-    ParameterFileStore, \
-    NoParameterShelf, \
-    output_type_registry
-from yt.units import UnitContainer
+from yt.data_objects.data_containers import data_object_registry
+from yt.data_objects.particle_filters import filter_registry
+from yt.data_objects.particle_unions import ParticleUnion
+from yt.data_objects.region_expression import RegionExpression
+from yt.fields.derived_field import DerivedField, ValidateSpatial
+from yt.fields.field_type_container import FieldTypeContainer
+from yt.fields.fluid_fields import setup_gradient_fields
+from yt.fields.particle_fields import DEP_MSG_SMOOTH_FIELD
+from yt.funcs import (
+    ensure_list,
+    issue_deprecation_warning,
+    iterable,
+    mylog,
+    set_intersection,
+    setdefaultattr,
+)
+from yt.geometry.coordinates.api import (
+    CartesianCoordinateHandler,
+    CoordinateHandler,
+    CylindricalCoordinateHandler,
+    GeographicCoordinateHandler,
+    InternalGeographicCoordinateHandler,
+    PolarCoordinateHandler,
+    SpectralCubeCoordinateHandler,
+    SphericalCoordinateHandler,
+)
+from yt.units import UnitContainer, _wrap_display_ytarray
 from yt.units.dimensions import current_mks
 from yt.units.unit_object import Unit, define_unit
-from yt.units.unit_systems import unit_system_registry
 from yt.units.unit_registry import UnitRegistry
-from yt.fields.derived_field import \
-    ValidateSpatial
-from yt.fields.fluid_fields import \
-    setup_gradient_fields
-from yt.fields.particle_fields import \
-    DEP_MSG_SMOOTH_FIELD
-from yt.data_objects.particle_filters import \
-    filter_registry
-from yt.data_objects.particle_unions import \
-    ParticleUnion
-from yt.data_objects.data_containers import \
-    data_object_registry
-from yt.utilities.minimal_representation import \
-    MinimalDataset
-from yt.units.yt_array import \
-    YTArray, \
-    YTQuantity
-from yt.units import \
-    _wrap_display_ytarray
-from yt.units.unit_systems import create_code_unit_system
-from yt.data_objects.region_expression import \
-    RegionExpression
-from yt.geometry.coordinates.api import \
-    CoordinateHandler, \
-    CartesianCoordinateHandler, \
-    PolarCoordinateHandler, \
-    CylindricalCoordinateHandler, \
-    SphericalCoordinateHandler, \
-    GeographicCoordinateHandler, \
-    SpectralCubeCoordinateHandler, \
-    InternalGeographicCoordinateHandler
+from yt.units.unit_systems import create_code_unit_system, unit_system_registry
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.cosmology import Cosmology
+from yt.utilities.exceptions import (
+    YTFieldNotFound,
+    YTGeometryNotSupported,
+    YTIllDefinedParticleFilter,
+    YTObjectNotImplemented,
+)
+from yt.utilities.minimal_representation import MinimalDataset
+from yt.utilities.parallel_tools.parallel_analysis_interface import parallel_root_only
+from yt.utilities.parameter_file_storage import (
+    NoParameterShelf,
+    ParameterFileStore,
+    output_type_registry,
+)
 
 # We want to support the movie format in the future.
 # When such a thing comes to pass, I'll move all the stuff that is constant up
diff --git a/yt/data_objects/tests/test_bbox.py b/yt/data_objects/tests/test_bbox.py
index 005e12f98c5..878e4b8adda 100644
--- a/yt/data_objects/tests/test_bbox.py
+++ b/yt/data_objects/tests/test_bbox.py
@@ -2,10 +2,7 @@
 
 import numpy as np
 
-from yt.testing import \
-    fake_amr_ds, \
-    assert_equal, \
-    assert_allclose_units
+from yt.testing import assert_allclose_units, assert_equal, fake_amr_ds
 
 
 def test_object_bbox():
diff --git a/yt/data_objects/tests/test_boolean_regions.py b/yt/data_objects/tests/test_boolean_regions.py
index a4cca05b178..babf213933f 100644
--- a/yt/data_objects/tests/test_boolean_regions.py
+++ b/yt/data_objects/tests/test_boolean_regions.py
@@ -1,8 +1,7 @@
-from yt.testing import \
-    fake_amr_ds, \
-    assert_array_equal
 import numpy as np
 
+from yt.testing import assert_array_equal, fake_amr_ds
+
 # We use morton indices in this test because they are single floating point
 # values that uniquely identify each cell.  That's a convenient way to compare
 # inclusion in set operations, since there are no duplicates.
diff --git a/yt/data_objects/tests/test_chunking.py b/yt/data_objects/tests/test_chunking.py
index 6ec67a96be2..f70673c94db 100644
--- a/yt/data_objects/tests/test_chunking.py
+++ b/yt/data_objects/tests/test_chunking.py
@@ -1,9 +1,6 @@
-from yt.testing import \
-    fake_random_ds, \
-    assert_equal, \
-    assert_true
-from yt.units.yt_array import \
-    uconcatenate
+from yt.testing import assert_equal, assert_true, fake_random_ds
+from yt.units.yt_array import uconcatenate
+
 
 def _get_dobjs(c):
     dobjs = [("sphere", ("center", (1.0, "unitary"))),
diff --git a/yt/data_objects/tests/test_clone.py b/yt/data_objects/tests/test_clone.py
index 8b3087b2b91..4c9339dc76b 100644
--- a/yt/data_objects/tests/test_clone.py
+++ b/yt/data_objects/tests/test_clone.py
@@ -1,7 +1,5 @@
-from yt.testing import \
-    fake_random_ds, \
-    assert_equal, \
-    assert_array_equal
+from yt.testing import assert_array_equal, assert_equal, fake_random_ds
+
 
 def test_clone_sphere():
     # Now we test that we can get different radial velocities based on field
diff --git a/yt/data_objects/tests/test_compose.py b/yt/data_objects/tests/test_compose.py
index c8a1ca66909..346d9ad9432 100644
--- a/yt/data_objects/tests/test_compose.py
+++ b/yt/data_objects/tests/test_compose.py
@@ -1,12 +1,8 @@
 import numpy as np
 
-from yt.testing import \
-    assert_array_equal, \
-    fake_amr_ds, \
-    fake_random_ds
-from yt.units.yt_array import \
-    YTArray, \
-    uintersect1d
+from yt.testing import assert_array_equal, fake_amr_ds, fake_random_ds
+from yt.units.yt_array import YTArray, uintersect1d
+
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/data_objects/tests/test_connected_sets.py b/yt/data_objects/tests/test_connected_sets.py
index af5aa034b38..f8a4ceeb21b 100644
--- a/yt/data_objects/tests/test_connected_sets.py
+++ b/yt/data_objects/tests/test_connected_sets.py
@@ -1,6 +1,7 @@
 from yt.testing import fake_random_ds
 from yt.utilities.answer_testing.level_sets_tests import ExtractConnectedSetsTest
 
+
 def test_connected_sets():
     ds = fake_random_ds(16, nprocs=8, particles=16**3)
     data_source = ds.disk([0.5, 0.5, 0.5], [0., 0., 1.], (8, 'kpc'), (1, 'kpc'))
diff --git a/yt/data_objects/tests/test_covering_grid.py b/yt/data_objects/tests/test_covering_grid.py
index 6738980dafd..a7624320a69 100644
--- a/yt/data_objects/tests/test_covering_grid.py
+++ b/yt/data_objects/tests/test_covering_grid.py
@@ -1,19 +1,23 @@
 import numpy as np
 
-from yt.fields.derived_field import \
-    ValidateParameter
-from yt.frontends.stream.data_structures import load_particles
-from yt.testing import fake_random_ds, assert_equal, assert_almost_equal, \
-    fake_octree_ds, requires_file, requires_module
 from yt.convenience import load
-from yt.testing import \
-    assert_array_equal
+from yt.fields.derived_field import ValidateParameter
+from yt.frontends.stream.data_structures import load_particles
+from yt.testing import (
+    assert_almost_equal,
+    assert_array_equal,
+    assert_equal,
+    fake_octree_ds,
+    fake_random_ds,
+    requires_file,
+    requires_module,
+)
+from yt.units import kpc
 
 # cylindrical data for covering_grid test
 cyl_2d = "WDMerger_hdf5_chk_1000/WDMerger_hdf5_chk_1000.hdf5"
 cyl_3d = "MHD_Cyl3d_hdf5_plt_cnt_0100/MHD_Cyl3d_hdf5_plt_cnt_0100.hdf5"
 
-from yt.units import kpc
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/data_objects/tests/test_cutting_plane.py b/yt/data_objects/tests/test_cutting_plane.py
index 7c938856aa6..a50a963ba27 100644
--- a/yt/data_objects/tests/test_cutting_plane.py
+++ b/yt/data_objects/tests/test_cutting_plane.py
@@ -1,8 +1,9 @@
-from yt.testing import assert_equal, fake_random_ds
-from yt.units.unit_object import Unit
 import os
 import tempfile
 
+from yt.testing import assert_equal, fake_random_ds
+from yt.units.unit_object import Unit
+
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/data_objects/tests/test_data_collection.py b/yt/data_objects/tests/test_data_collection.py
index 07ab66270d5..5a0ca998964 100644
--- a/yt/data_objects/tests/test_data_collection.py
+++ b/yt/data_objects/tests/test_data_collection.py
@@ -1,9 +1,7 @@
 import numpy as np
 
-from yt.testing import \
-    fake_random_ds, \
-    assert_equal, \
-    assert_rel_equal
+from yt.testing import assert_equal, assert_rel_equal, fake_random_ds
+
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/data_objects/tests/test_data_containers.py b/yt/data_objects/tests/test_data_containers.py
index 328211fc380..0031a49359a 100644
--- a/yt/data_objects/tests/test_data_containers.py
+++ b/yt/data_objects/tests/test_data_containers.py
@@ -10,10 +10,16 @@
 
 from yt.data_objects.data_containers import YTDataContainer
 from yt.data_objects.particle_filters import particle_filter
-from yt.testing import assert_equal, fake_random_ds, fake_amr_ds,\
-    fake_particle_ds, requires_module
+from yt.testing import (
+    assert_equal,
+    fake_amr_ds,
+    fake_particle_ds,
+    fake_random_ds,
+    requires_module,
+)
 from yt.utilities.exceptions import YTFieldNotFound
 
+
 class TestDataContainers(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
diff --git a/yt/data_objects/tests/test_dataset_access.py b/yt/data_objects/tests/test_dataset_access.py
index 53aa828e2c5..3083d7b8245 100644
--- a/yt/data_objects/tests/test_dataset_access.py
+++ b/yt/data_objects/tests/test_dataset_access.py
@@ -1,13 +1,14 @@
 import numpy as np
 from nose.tools import assert_raises
 
-from yt.testing import \
-    assert_equal, \
-    assert_almost_equal, \
-    fake_amr_ds, \
-    fake_particle_ds, \
-    fake_random_ds, \
-    requires_file
+from yt.testing import (
+    assert_almost_equal,
+    assert_equal,
+    fake_amr_ds,
+    fake_particle_ds,
+    fake_random_ds,
+    requires_file,
+)
 from yt.utilities.answer_testing.framework import data_dir_load
 from yt.utilities.exceptions import YTDimensionalityError
 from yt.visualization.line_plot import LineBuffer
diff --git a/yt/data_objects/tests/test_derived_quantities.py b/yt/data_objects/tests/test_derived_quantities.py
index c2566cca1ce..9007525c689 100644
--- a/yt/data_objects/tests/test_derived_quantities.py
+++ b/yt/data_objects/tests/test_derived_quantities.py
@@ -1,18 +1,19 @@
 
 
 import numpy as np
-import yt
-
-from yt.testing import \
-    fake_random_ds, \
-    fake_sph_orientation_ds, \
-    fake_particle_ds, \
-    assert_almost_equal, \
-    assert_equal, \
-    assert_rel_equal, \
-    requires_file
 
+import yt
 from yt import particle_filter
+from yt.testing import (
+    assert_almost_equal,
+    assert_equal,
+    assert_rel_equal,
+    fake_particle_ds,
+    fake_random_ds,
+    fake_sph_orientation_ds,
+    requires_file,
+)
+
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/data_objects/tests/test_ellipsoid.py b/yt/data_objects/tests/test_ellipsoid.py
index 53f3642a548..a3c2bc84b1a 100644
--- a/yt/data_objects/tests/test_ellipsoid.py
+++ b/yt/data_objects/tests/test_ellipsoid.py
@@ -1,8 +1,7 @@
 import numpy as np
 
-from yt.testing import \
-    fake_random_ds, \
-    assert_array_less
+from yt.testing import assert_array_less, fake_random_ds
+
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/data_objects/tests/test_exclude_functions.py b/yt/data_objects/tests/test_exclude_functions.py
index c16fff04b4f..af7b26d89a8 100644
--- a/yt/data_objects/tests/test_exclude_functions.py
+++ b/yt/data_objects/tests/test_exclude_functions.py
@@ -1,7 +1,7 @@
 import numpy as np
 
-from yt.testing import fake_random_ds, assert_equal
 from yt.frontends.stream.data_structures import load_uniform_grid
+from yt.testing import assert_equal, fake_random_ds
 
 
 def test_exclude_above():
@@ -88,4 +88,3 @@ def test_inside_outside():
     only_threes = ad.include_outside('density', 0.9e6, 2.1e6, 'g/m**3')
     assert np.all(only_threes['density'] == 3)
     assert len(only_threes['density']) == 10
- 
diff --git a/yt/data_objects/tests/test_extract_regions.py b/yt/data_objects/tests/test_extract_regions.py
index a20ace79a53..02e3e2457aa 100644
--- a/yt/data_objects/tests/test_extract_regions.py
+++ b/yt/data_objects/tests/test_extract_regions.py
@@ -1,12 +1,14 @@
 import numpy as np
 
 from yt.convenience import load
-from yt.testing import \
-    fake_random_ds, \
-    fake_amr_ds, \
-    assert_equal, \
-    assert_almost_equal, \
-    requires_file
+from yt.testing import (
+    assert_almost_equal,
+    assert_equal,
+    fake_amr_ds,
+    fake_random_ds,
+    requires_file,
+)
+
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/data_objects/tests/test_firefly.py b/yt/data_objects/tests/test_firefly.py
index 04f284a0e52..4fd396cf16e 100644
--- a/yt/data_objects/tests/test_firefly.py
+++ b/yt/data_objects/tests/test_firefly.py
@@ -1,6 +1,8 @@
-from yt.testing import fake_particle_ds, requires_module
 import tempfile
 
+from yt.testing import fake_particle_ds, requires_module
+
+
 @requires_module('firefly_api')
 def test_firefly_JSON_object():
     tmpdir = tempfile.mkdtemp()
@@ -13,4 +15,3 @@ def test_firefly_JSON_object():
         coordinate_units = 'cm',
         dataset_name='test')
     reader.dumpToJSON()
-
diff --git a/yt/data_objects/tests/test_fluxes.py b/yt/data_objects/tests/test_fluxes.py
index 9843db17770..ae26154a4d8 100644
--- a/yt/data_objects/tests/test_fluxes.py
+++ b/yt/data_objects/tests/test_fluxes.py
@@ -1,12 +1,12 @@
 import os
 import shutil
 import tempfile
+from unittest import TestCase
 
 import numpy as np
 
-from unittest import TestCase
+from yt.testing import assert_almost_equal, assert_equal, fake_random_ds
 
-from yt.testing import fake_random_ds, assert_almost_equal, assert_equal
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/data_objects/tests/test_glue.py b/yt/data_objects/tests/test_glue.py
index 42484054c9c..9f19b6b38d6 100644
--- a/yt/data_objects/tests/test_glue.py
+++ b/yt/data_objects/tests/test_glue.py
@@ -3,6 +3,7 @@
 from yt.config import ytcfg
 from yt.testing import fake_random_ds, requires_module
 
+
 def setup_func():
     ytcfg["yt", "__withintesting"] = "True"
 
diff --git a/yt/data_objects/tests/test_image_array.py b/yt/data_objects/tests/test_image_array.py
index f6bd81d8504..97f035ecd88 100644
--- a/yt/data_objects/tests/test_image_array.py
+++ b/yt/data_objects/tests/test_image_array.py
@@ -1,13 +1,13 @@
-import numpy as np
 import os
-import tempfile
 import shutil
+import tempfile
 import unittest
 import warnings
+
+import numpy as np
+
 from yt.data_objects.image_array import ImageArray
-from yt.testing import \
-    assert_equal, \
-    requires_module
+from yt.testing import assert_equal, requires_module
 
 
 def setup():
diff --git a/yt/data_objects/tests/test_numpy_ops.py b/yt/data_objects/tests/test_numpy_ops.py
index 4de052dbd83..3a989010378 100644
--- a/yt/data_objects/tests/test_numpy_ops.py
+++ b/yt/data_objects/tests/test_numpy_ops.py
@@ -1,6 +1,7 @@
-from yt.testing import fake_random_ds, fake_amr_ds, assert_equal
 import numpy as np
 
+from yt.testing import assert_equal, fake_amr_ds, fake_random_ds
+
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/data_objects/tests/test_octree.py b/yt/data_objects/tests/test_octree.py
index 74d65d19965..2588fcee11c 100644
--- a/yt/data_objects/tests/test_octree.py
+++ b/yt/data_objects/tests/test_octree.py
@@ -1,11 +1,13 @@
-from yt.testing import \
-    fake_sph_grid_ds, assert_almost_equal
-from yt.data_objects.construction_data_containers import YTOctree
-import tempfile
 import os
 import shutil
+import tempfile
+
 import numpy as np
 
+from yt.data_objects.construction_data_containers import YTOctree
+from yt.testing import assert_almost_equal, fake_sph_grid_ds
+
+
 def test_building_tree():
     '''
     Test function to build an octree and make sure correct number of particles
diff --git a/yt/data_objects/tests/test_ortho_rays.py b/yt/data_objects/tests/test_ortho_rays.py
index de5b808d1e3..0958d775871 100644
--- a/yt/data_objects/tests/test_ortho_rays.py
+++ b/yt/data_objects/tests/test_ortho_rays.py
@@ -1,8 +1,6 @@
 import numpy as np
 
-from yt.testing import \
-    fake_random_ds, \
-    assert_equal
+from yt.testing import assert_equal, fake_random_ds
 
 
 def test_ortho_ray():
diff --git a/yt/data_objects/tests/test_particle_filter.py b/yt/data_objects/tests/test_particle_filter.py
index 34f3364c090..62a6082d78b 100644
--- a/yt/data_objects/tests/test_particle_filter.py
+++ b/yt/data_objects/tests/test_particle_filter.py
@@ -1,17 +1,16 @@
 
 
-import numpy as np
 import os
 import shutil
 import tempfile
 
+import numpy as np
 from nose.tools import assert_raises
 
 from yt.data_objects.particle_filters import add_particle_filter, particle_filter
 from yt.testing import assert_equal, fake_random_ds, fake_sph_grid_ds
+from yt.utilities.exceptions import YTIllDefinedFilter, YTIllDefinedParticleFilter
 from yt.visualization.plot_window import ProjectionPlot
-from yt.utilities.exceptions import YTIllDefinedFilter, \
-    YTIllDefinedParticleFilter
 
 
 def test_add_particle_filter():
diff --git a/yt/data_objects/tests/test_particle_trajectories.py b/yt/data_objects/tests/test_particle_trajectories.py
index 7c01380e8b1..d7f9f16073f 100644
--- a/yt/data_objects/tests/test_particle_trajectories.py
+++ b/yt/data_objects/tests/test_particle_trajectories.py
@@ -1,17 +1,15 @@
 import glob
 import os
+
 import numpy as np
-from numpy.testing import \
-    assert_raises
+from numpy.testing import assert_raises
 
 from yt.config import ytcfg
+from yt.data_objects.particle_filters import particle_filter
 from yt.data_objects.time_series import DatasetSeries
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    GenericArrayTest
 from yt.testing import fake_particle_ds
+from yt.utilities.answer_testing.framework import GenericArrayTest, requires_ds
 from yt.utilities.exceptions import YTIllDefinedParticleData
-from yt.data_objects.particle_filters import particle_filter
 
 
 def setup():
diff --git a/yt/data_objects/tests/test_pickle.py b/yt/data_objects/tests/test_pickle.py
index b1b53a7b9fa..0a88c3bfcc1 100644
--- a/yt/data_objects/tests/test_pickle.py
+++ b/yt/data_objects/tests/test_pickle.py
@@ -1,8 +1,8 @@
-import pickle
 import os
+import pickle
 import tempfile
-from yt.testing \
-    import fake_random_ds, assert_equal
+
+from yt.testing import assert_equal, fake_random_ds
 
 
 def setup():
diff --git a/yt/data_objects/tests/test_points.py b/yt/data_objects/tests/test_points.py
index caacb5221fc..4077120c61a 100644
--- a/yt/data_objects/tests/test_points.py
+++ b/yt/data_objects/tests/test_points.py
@@ -1,7 +1,8 @@
 import numpy as np
+
 import yt
+from yt.testing import assert_equal, fake_random_ds
 
-from yt.testing import fake_random_ds, assert_equal
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/data_objects/tests/test_profiles.py b/yt/data_objects/tests/test_profiles.py
index 2ca61f49d25..2342a46a336 100644
--- a/yt/data_objects/tests/test_profiles.py
+++ b/yt/data_objects/tests/test_profiles.py
@@ -1,24 +1,23 @@
-import numpy as np
 import os
 import shutil
 import tempfile
 import unittest
-import yt
 
-from yt.utilities.exceptions import \
-    YTProfileDataShape
+import numpy as np
+
+import yt
 from yt.data_objects.particle_filters import add_particle_filter
-from yt.data_objects.profiles import Profile1D, Profile2D, Profile3D,\
-    create_profile
-from yt.testing import \
-    assert_equal, \
-    assert_raises,\
-    assert_rel_equal, \
-    fake_random_ds, \
-    fake_sph_orientation_ds, \
-    requires_module
-from yt.utilities.exceptions import YTIllDefinedProfile
-from yt.visualization.profile_plotter import ProfilePlot, PhasePlot
+from yt.data_objects.profiles import Profile1D, Profile2D, Profile3D, create_profile
+from yt.testing import (
+    assert_equal,
+    assert_raises,
+    assert_rel_equal,
+    fake_random_ds,
+    fake_sph_orientation_ds,
+    requires_module,
+)
+from yt.utilities.exceptions import YTIllDefinedProfile, YTProfileDataShape
+from yt.visualization.profile_plotter import PhasePlot, ProfilePlot
 
 _fields = ("density", "temperature", "dinosaurs", "tribbles")
 _units = ("g/cm**3", "K", "dyne", "erg")
diff --git a/yt/data_objects/tests/test_projection.py b/yt/data_objects/tests/test_projection.py
index b54fd3b8679..73a4e6969b9 100644
--- a/yt/data_objects/tests/test_projection.py
+++ b/yt/data_objects/tests/test_projection.py
@@ -1,13 +1,11 @@
-import numpy as np
-from yt.testing import \
-    fake_random_ds, \
-    assert_equal, \
-    assert_rel_equal, \
-    fake_amr_ds
-from yt.units.unit_object import Unit
 import os
 import tempfile
 
+import numpy as np
+
+from yt.testing import assert_equal, assert_rel_equal, fake_amr_ds, fake_random_ds
+from yt.units.unit_object import Unit
+
 LENGTH_UNIT = 2.0
 
 
diff --git a/yt/data_objects/tests/test_rays.py b/yt/data_objects/tests/test_rays.py
index 756d62e0429..6ef502e1ddf 100644
--- a/yt/data_objects/tests/test_rays.py
+++ b/yt/data_objects/tests/test_rays.py
@@ -1,14 +1,9 @@
 import numpy as np
 
-from yt import \
-    load
-from yt.testing import \
-    fake_random_ds, \
-    assert_equal, \
-    assert_rel_equal, \
-    requires_file
-from yt.units.yt_array import \
-    uconcatenate
+from yt import load
+from yt.testing import assert_equal, assert_rel_equal, fake_random_ds, requires_file
+from yt.units.yt_array import uconcatenate
+
 
 def test_ray():
     for nproc in [1, 2, 4, 8]:
diff --git a/yt/data_objects/tests/test_refinement.py b/yt/data_objects/tests/test_refinement.py
index 38966f20a50..ca5a2010f90 100644
--- a/yt/data_objects/tests/test_refinement.py
+++ b/yt/data_objects/tests/test_refinement.py
@@ -1,9 +1,9 @@
-from yt.testing import \
-    assert_array_equal, \
-    assert_equal
-import yt
 import numpy as np
 
+import yt
+from yt.testing import assert_array_equal, assert_equal
+
+
 def setup_fake_refby():
     refine_by=np.array([5, 1, 1])
     top_grid_dim = [100,  10, 2]
diff --git a/yt/data_objects/tests/test_regions.py b/yt/data_objects/tests/test_regions.py
index ef6d69e369b..557396abe60 100644
--- a/yt/data_objects/tests/test_regions.py
+++ b/yt/data_objects/tests/test_regions.py
@@ -1,9 +1,7 @@
-from yt.testing import \
-    assert_array_equal, \
-    fake_amr_ds, \
-    fake_random_ds
+from yt.testing import assert_array_equal, fake_amr_ds, fake_random_ds
 from yt.units import cm
 
+
 def test_box_creation():
 
     # test that creating a region with left and right edge
diff --git a/yt/data_objects/tests/test_slice.py b/yt/data_objects/tests/test_slice.py
index 8e8a2e71c87..e7e3866d36b 100644
--- a/yt/data_objects/tests/test_slice.py
+++ b/yt/data_objects/tests/test_slice.py
@@ -1,8 +1,9 @@
 import os
-import numpy as np
 import tempfile
-from yt.testing import \
-    fake_random_ds, assert_equal
+
+import numpy as np
+
+from yt.testing import assert_equal, fake_random_ds
 from yt.units.unit_object import Unit
 
 
diff --git a/yt/data_objects/tests/test_sph_data_objects.py b/yt/data_objects/tests/test_sph_data_objects.py
index 1ba56a70f35..a00d1b355b4 100644
--- a/yt/data_objects/tests/test_sph_data_objects.py
+++ b/yt/data_objects/tests/test_sph_data_objects.py
@@ -1,9 +1,8 @@
 import numpy as np
 
-from yt.testing import \
-    assert_equal, \
-    fake_sph_orientation_ds, fake_sph_grid_ds
 from yt import SlicePlot
+from yt.testing import assert_equal, fake_sph_grid_ds, fake_sph_orientation_ds
+
 
 def test_point():
     ds = fake_sph_orientation_ds()
@@ -322,4 +321,3 @@ def test_covering_grid_gather():
     cg_dens = cg[field].to('g*cm**-3').d
 
     assert_equal(ag_dens, cg_dens)
-
diff --git a/yt/data_objects/tests/test_spheres.py b/yt/data_objects/tests/test_spheres.py
index 293fd29e52d..216300800c3 100644
--- a/yt/data_objects/tests/test_spheres.py
+++ b/yt/data_objects/tests/test_spheres.py
@@ -2,9 +2,13 @@
 from numpy.testing import assert_array_equal
 
 from yt.data_objects.profiles import create_profile
-from yt.testing import fake_random_ds, assert_equal, periodicity_cases, \
-    assert_raises, requires_module
-
+from yt.testing import (
+    assert_equal,
+    assert_raises,
+    fake_random_ds,
+    periodicity_cases,
+    requires_module,
+)
 from yt.utilities.exceptions import YTException
 
 
diff --git a/yt/data_objects/tests/test_streamlines.py b/yt/data_objects/tests/test_streamlines.py
index 06baedc8f50..880624d7895 100644
--- a/yt/data_objects/tests/test_streamlines.py
+++ b/yt/data_objects/tests/test_streamlines.py
@@ -1,11 +1,9 @@
 import numpy as np
 
-from yt.testing import \
-    fake_random_ds, \
-    assert_rel_equal, \
-    assert_equal
+from yt.testing import assert_equal, assert_rel_equal, fake_random_ds
 from yt.visualization.streamlines import Streamlines
 
+
 def setup():
     from yt.config import ytcfg
     ytcfg["yt","__withintesting"] = "True"
diff --git a/yt/data_objects/tests/test_time_series.py b/yt/data_objects/tests/test_time_series.py
index 6d073657fef..0db603bc74f 100644
--- a/yt/data_objects/tests/test_time_series.py
+++ b/yt/data_objects/tests/test_time_series.py
@@ -1,10 +1,11 @@
-from yt.data_objects.time_series import get_filenames_from_glob_pattern
-
-from pathlib import Path
 import os
 import tempfile
+from pathlib import Path
+
+from yt.data_objects.time_series import get_filenames_from_glob_pattern
 from yt.testing import assert_raises
 
+
 def test_pattern_expansion():
     file_list = ["fake_data_file_{}".format(str(i).zfill(4)) for i in range(10)]
 
diff --git a/yt/data_objects/time_series.py b/yt/data_objects/time_series.py
index 2c24290e582..7e08f1fafc4 100644
--- a/yt/data_objects/time_series.py
+++ b/yt/data_objects/time_series.py
@@ -1,37 +1,33 @@
-import inspect
 import functools
 import glob
-import numpy as np
+import inspect
 import os
 import weakref
-
 from functools import wraps
 
-from yt.convenience import load
+import numpy as np
+
 from yt.config import ytcfg
+from yt.convenience import load
+from yt.data_objects.analyzer_objects import (
+    AnalysisTask,
+    analysis_task_registry,
+    create_quantity_proxy,
+)
 from yt.data_objects.data_containers import data_object_registry
-from yt.data_objects.derived_quantities import \
-    derived_quantity_registry
-from yt.data_objects.analyzer_objects import \
-    create_quantity_proxy, \
-    analysis_task_registry, \
-    AnalysisTask
-from yt.data_objects.particle_trajectories import \
-    ParticleTrajectories
-from yt.funcs import \
-    iterable, \
-    ensure_list, \
-    mylog, \
-    issue_deprecation_warning
+from yt.data_objects.derived_quantities import derived_quantity_registry
+from yt.data_objects.particle_trajectories import ParticleTrajectories
+from yt.funcs import ensure_list, issue_deprecation_warning, iterable, mylog
 from yt.units.yt_array import YTArray, YTQuantity
-from yt.utilities.exceptions import \
-    YTException, \
-    YTOutputNotIdentified
-from yt.utilities.parallel_tools.parallel_analysis_interface \
-    import parallel_objects, parallel_root_only, communication_system
-from yt.utilities.parameter_file_storage import \
-    simulation_time_series_registry
-     
+from yt.utilities.exceptions import YTException, YTOutputNotIdentified
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    communication_system,
+    parallel_objects,
+    parallel_root_only,
+)
+from yt.utilities.parameter_file_storage import simulation_time_series_registry
+
+
 class AnalysisTaskProxy:
     def __init__(self, time_series):
         self.time_series = time_series
diff --git a/yt/data_objects/unions.py b/yt/data_objects/unions.py
index 2feabf58397..43d39c2bb4b 100644
--- a/yt/data_objects/unions.py
+++ b/yt/data_objects/unions.py
@@ -1,5 +1,6 @@
 from yt.funcs import ensure_list
 
+
 class Union:
     _union_type = ""
     def __init__(self, name, sub_types):
diff --git a/yt/data_objects/unstructured_mesh.py b/yt/data_objects/unstructured_mesh.py
index 636f8f40100..9df16c82941 100644
--- a/yt/data_objects/unstructured_mesh.py
+++ b/yt/data_objects/unstructured_mesh.py
@@ -1,14 +1,11 @@
 import numpy as np
 
+import yt.geometry.particle_deposit as particle_deposit
+from yt.data_objects.data_containers import YTSelectionContainer
 from yt.funcs import mylog
-from yt.utilities.exceptions import \
-    YTParticleDepositionNotImplemented
-from yt.utilities.lib.mesh_utilities import \
-    fill_fcoords, fill_fwidths
+from yt.utilities.exceptions import YTParticleDepositionNotImplemented
+from yt.utilities.lib.mesh_utilities import fill_fcoords, fill_fwidths
 
-from yt.data_objects.data_containers import \
-    YTSelectionContainer
-import yt.geometry.particle_deposit as particle_deposit
 
 class UnstructuredMesh(YTSelectionContainer):
     # This is a base class, not meant to be used directly.
@@ -214,4 +211,3 @@ def select(self, selector, source, dest, offset):
         # Note: this likely will not work with vector fields.
         dest[offset:offset+count] = source.flat[mask]
         return count
-
diff --git a/yt/exthook.py b/yt/exthook.py
index a1c18368eba..f4ea3dfd586 100644
--- a/yt/exthook.py
+++ b/yt/exthook.py
@@ -22,7 +22,6 @@
 # This source code was originally in flask/exthook.py
 import os
 import sys
-import os
 
 
 class ExtensionImporter:
diff --git a/yt/fields/angular_momentum.py b/yt/fields/angular_momentum.py
index b94ee50e0dd..277f43abfa3 100644
--- a/yt/fields/angular_momentum.py
+++ b/yt/fields/angular_momentum.py
@@ -1,17 +1,14 @@
 import numpy as np
 
-from .derived_field import \
-    ValidateParameter
+from yt.utilities.lib.misc_utilities import (
+    obtain_position_vector,
+    obtain_relative_velocity_vector,
+)
 
-from .field_plugin_registry import \
-    register_field_plugin
+from .derived_field import ValidateParameter
+from .field_plugin_registry import register_field_plugin
+from .vector_operations import create_magnitude_field
 
-from .vector_operations import \
-    create_magnitude_field
-
-from yt.utilities.lib.misc_utilities import \
-    obtain_position_vector, \
-    obtain_relative_velocity_vector
 
 @register_field_plugin
 def setup_angular_momentum(registry, ftype = "gas", slice_info = None):
diff --git a/yt/fields/api.py b/yt/fields/api.py
index 0819b2ba558..8ec272cb8df 100644
--- a/yt/fields/api.py
+++ b/yt/fields/api.py
@@ -1,33 +1,27 @@
-from .field_plugin_registry import \
-    register_field_plugin, \
-    field_plugins
-
-from . import angular_momentum
-from . import astro_fields
-from . import cosmology_fields
-from . import fluid_fields
-from . import fluid_vector_fields
-from . import magnetic_field
-from . import geometric_fields
-from . import particle_fields
 #from . import species_fields
-from . import vector_operations
-from . import local_fields
-from . import my_plugin_fields
-
+from . import (
+    angular_momentum,
+    astro_fields,
+    cosmology_fields,
+    fluid_fields,
+    fluid_vector_fields,
+    geometric_fields,
+    local_fields,
+    magnetic_field,
+    my_plugin_fields,
+    particle_fields,
+    vector_operations,
+)
+from .derived_field import (
+    DerivedField,
+    ValidateDataField,
+    ValidateGridType,
+    ValidateParameter,
+    ValidateProperty,
+    ValidateSpatial,
+)
+from .field_detector import FieldDetector
+from .field_info_container import FieldInfoContainer
+from .field_plugin_registry import field_plugins, register_field_plugin
 from .local_fields import add_field, derived_field
-
-
-from .derived_field import \
-    DerivedField, \
-    ValidateParameter, \
-    ValidateDataField, \
-    ValidateProperty, \
-    ValidateSpatial, \
-    ValidateGridType
-from .field_detector import \
-    FieldDetector
-from .field_info_container import \
-    FieldInfoContainer
-from .xray_emission_fields import \
-    add_xray_emissivity_field
\ No newline at end of file
+from .xray_emission_fields import add_xray_emissivity_field
diff --git a/yt/fields/astro_fields.py b/yt/fields/astro_fields.py
index b9f0bf43b0d..17807e488f3 100644
--- a/yt/fields/astro_fields.py
+++ b/yt/fields/astro_fields.py
@@ -1,9 +1,7 @@
 import numpy as np
 
-from .derived_field import \
-    ValidateParameter
-from .field_plugin_registry import \
-    register_field_plugin
+from .derived_field import ValidateParameter
+from .field_plugin_registry import register_field_plugin
 
 
 @register_field_plugin
diff --git a/yt/fields/cosmology_fields.py b/yt/fields/cosmology_fields.py
index bfaa998b49e..90296cbeedc 100644
--- a/yt/fields/cosmology_fields.py
+++ b/yt/fields/cosmology_fields.py
@@ -1,10 +1,7 @@
-from .derived_field import \
-    ValidateParameter
-from .field_exceptions import \
-    NeedsConfiguration, \
-    NeedsParameter
-from .field_plugin_registry import \
-    register_field_plugin
+from .derived_field import ValidateParameter
+from .field_exceptions import NeedsConfiguration, NeedsParameter
+from .field_plugin_registry import register_field_plugin
+
 
 @register_field_plugin
 def setup_cosmology_fields(registry, ftype = "gas", slice_info = None):
diff --git a/yt/fields/derived_field.py b/yt/fields/derived_field.py
index 216d28b85da..5236f6bc651 100644
--- a/yt/fields/derived_field.py
+++ b/yt/fields/derived_field.py
@@ -3,23 +3,20 @@
 import re
 import warnings
 
-from yt.funcs import \
-    ensure_list, \
-    VisibleDeprecationWarning
-from .field_exceptions import \
-    NeedsGridType, \
-    NeedsOriginalGrid, \
-    NeedsDataField, \
-    NeedsProperty, \
-    NeedsParameter, \
-    FieldUnitsError
-from .field_detector import \
-    FieldDetector
-from yt.units.unit_object import \
-    Unit
 import yt.units.dimensions as ytdims
-from yt.utilities.exceptions import \
-    YTFieldNotFound
+from yt.funcs import VisibleDeprecationWarning, ensure_list
+from yt.units.unit_object import Unit
+from yt.utilities.exceptions import YTFieldNotFound
+
+from .field_detector import FieldDetector
+from .field_exceptions import (
+    FieldUnitsError,
+    NeedsDataField,
+    NeedsGridType,
+    NeedsOriginalGrid,
+    NeedsParameter,
+    NeedsProperty,
+)
 
 
 def TranslationFunc(field_name):
diff --git a/yt/fields/domain_context.py b/yt/fields/domain_context.py
index 16d36577ba9..6a6b69e46d6 100644
--- a/yt/fields/domain_context.py
+++ b/yt/fields/domain_context.py
@@ -11,4 +11,3 @@ def __init__(cls, name, b, d):
 
     def __init__(self, ds):
         self.ds = ds
-
diff --git a/yt/fields/field_detector.py b/yt/fields/field_detector.py
index 128aca67eab..9bf71d0f073 100644
--- a/yt/fields/field_detector.py
+++ b/yt/fields/field_detector.py
@@ -1,8 +1,10 @@
-import numpy as np
 from collections import defaultdict
+
+import numpy as np
+
 from yt.units.yt_array import YTArray
-from .field_exceptions import \
-    NeedsGridType
+
+from .field_exceptions import NeedsGridType
 
 fp_units = {
     'bulk_velocity' : 'cm/s',
@@ -279,4 +281,3 @@ def fwidth(self):
         if not self.flat:
             fw.shape = (self.nd, self.nd, self.nd, 3)
         return self.ds.arr(fw, units = "code_length")
-
diff --git a/yt/fields/field_exceptions.py b/yt/fields/field_exceptions.py
index c5cdef171f1..b2970803316 100644
--- a/yt/fields/field_exceptions.py
+++ b/yt/fields/field_exceptions.py
@@ -40,4 +40,3 @@ def __str__(self):
 
 class FieldUnitsError(Exception):
     pass
-
diff --git a/yt/fields/field_functions.py b/yt/fields/field_functions.py
index cfbe7a283fe..e1f53dd52c5 100644
--- a/yt/fields/field_functions.py
+++ b/yt/fields/field_functions.py
@@ -1,7 +1,7 @@
 import numpy as np
 
-from yt.utilities.lib.misc_utilities import \
-    obtain_position_vector
+from yt.utilities.lib.misc_utilities import obtain_position_vector
+
 
 def get_radius(data, field_prefix, ftype):
     unit_system = data.ds.unit_system
diff --git a/yt/fields/field_info_container.py b/yt/fields/field_info_container.py
index e3c63b06124..3ebbed2da43 100644
--- a/yt/fields/field_info_container.py
+++ b/yt/fields/field_info_container.py
@@ -1,27 +1,25 @@
-import numpy as np
-from numbers import Number as numeric_type
 import warnings
+from numbers import Number as numeric_type
+
+import numpy as np
 
 from yt.funcs import mylog, only_on_root
-from yt.geometry.geometry_handler import \
-    is_curvilinear
-from yt.units.unit_object import Unit
+from yt.geometry.geometry_handler import is_curvilinear
 from yt.units.dimensions import dimensionless
-from .derived_field import \
-    DerivedField, \
-    NullFunc, \
-    TranslationFunc
-from yt.utilities.exceptions import \
-    YTFieldNotFound
-from .field_plugin_registry import \
-    field_plugins
-from .particle_fields import \
-    add_union_field, \
-    particle_deposition_functions, \
-    particle_vector_functions, \
-    particle_scalar_functions, \
-    standard_particle_fields, \
-    sph_whitelist_fields
+from yt.units.unit_object import Unit
+from yt.utilities.exceptions import YTFieldNotFound
+
+from .derived_field import DerivedField, NullFunc, TranslationFunc
+from .field_plugin_registry import field_plugins
+from .particle_fields import (
+    add_union_field,
+    particle_deposition_functions,
+    particle_scalar_functions,
+    particle_vector_functions,
+    sph_whitelist_fields,
+    standard_particle_fields,
+)
+
 
 def tupleize(inp):
     if isinstance(inp, tuple):
diff --git a/yt/fields/field_type_container.py b/yt/fields/field_type_container.py
index 31eee8db606..3f61d5df636 100644
--- a/yt/fields/field_type_container.py
+++ b/yt/fields/field_type_container.py
@@ -2,11 +2,12 @@
 A proxy object for field descriptors, usually living as ds.fields.
 """
 
-import weakref
-import textwrap
 import inspect
-from yt.fields.derived_field import \
-    DerivedField
+import textwrap
+import weakref
+
+from yt.fields.derived_field import DerivedField
+
 
 def _fill_values(values):
     value = '<div class="rendered_html jp-RenderedHTMLCommon">' + \
diff --git a/yt/fields/fluid_fields.py b/yt/fields/fluid_fields.py
index 0a213e43409..5f6b5903e59 100644
--- a/yt/fields/fluid_fields.py
+++ b/yt/fields/fluid_fields.py
@@ -1,29 +1,19 @@
 import numpy as np
 
+from yt.funcs import mylog
+from yt.geometry.geometry_handler import is_curvilinear
 from yt.units.unit_object import Unit
+from yt.utilities.chemical_formulas import default_mu
+from yt.utilities.lib.misc_utilities import obtain_relative_velocity_vector
 
-from .derived_field import \
-    ValidateSpatial, \
-    ValidateParameter
-
-from .field_plugin_registry import \
-    register_field_plugin
-
-from yt.geometry.geometry_handler import \
-    is_curvilinear
-
-from .vector_operations import \
-    create_averaged_field, \
-    create_magnitude_field, \
-    create_vector_fields
+from .derived_field import ValidateParameter, ValidateSpatial
+from .field_plugin_registry import register_field_plugin
+from .vector_operations import (
+    create_averaged_field,
+    create_magnitude_field,
+    create_vector_fields,
+)
 
-from yt.utilities.chemical_formulas import \
-    default_mu
-
-from yt.utilities.lib.misc_utilities import \
-    obtain_relative_velocity_vector
-
-from yt.funcs import mylog
 
 @register_field_plugin
 def setup_fluid_fields(registry, ftype = "gas", slice_info = None):
diff --git a/yt/fields/fluid_vector_fields.py b/yt/fields/fluid_vector_fields.py
index 83b1adb180e..815977839a6 100644
--- a/yt/fields/fluid_vector_fields.py
+++ b/yt/fields/fluid_vector_fields.py
@@ -1,21 +1,12 @@
 import numpy as np
 
-from yt.fields.derived_field import \
-    ValidateSpatial, \
-    ValidateParameter
+from yt.fields.derived_field import ValidateParameter, ValidateSpatial
+from yt.funcs import just_one
+from yt.geometry.geometry_handler import is_curvilinear
 
-from .field_plugin_registry import \
-    register_field_plugin
+from .field_plugin_registry import register_field_plugin
+from .vector_operations import create_magnitude_field, create_squared_field
 
-from yt.funcs import \
-    just_one
-
-from yt.geometry.geometry_handler import \
-    is_curvilinear
-
-from .vector_operations import \
-    create_magnitude_field, \
-    create_squared_field
 
 @register_field_plugin
 def setup_fluid_vector_fields(registry, ftype = "gas", slice_info = None):
diff --git a/yt/fields/geometric_fields.py b/yt/fields/geometric_fields.py
index 3b8fa041fa3..5c638eaf1d1 100644
--- a/yt/fields/geometric_fields.py
+++ b/yt/fields/geometric_fields.py
@@ -1,23 +1,19 @@
 import numpy as np
 
-from .derived_field import \
-    ValidateParameter, \
-    ValidateSpatial
+from yt.utilities.lib.geometry_utils import compute_morton
+from yt.utilities.math_utils import (
+    get_cyl_r,
+    get_cyl_theta,
+    get_cyl_z,
+    get_sph_phi,
+    get_sph_r,
+    get_sph_theta,
+)
+
+from .derived_field import ValidateParameter, ValidateSpatial
+from .field_functions import get_periodic_rvec, get_radius
+from .field_plugin_registry import register_field_plugin
 
-from .field_functions import \
-    get_periodic_rvec, \
-    get_radius
-
-from .field_plugin_registry import \
-    register_field_plugin
-
-from yt.utilities.math_utils import \
-    get_cyl_r, get_cyl_theta, \
-    get_cyl_z, get_sph_r, \
-    get_sph_theta, get_sph_phi
-
-from yt.utilities.lib.geometry_utils import \
-    compute_morton
 
 @register_field_plugin
 def setup_geometric_fields(registry, ftype="gas", slice_info=None):
diff --git a/yt/fields/interpolated_fields.py b/yt/fields/interpolated_fields.py
index 28c08e1afc0..01fac1bee8f 100644
--- a/yt/fields/interpolated_fields.py
+++ b/yt/fields/interpolated_fields.py
@@ -1,9 +1,9 @@
 from yt.fields.local_fields import add_field
-
-from yt.utilities.linear_interpolators import \
-    UnilinearFieldInterpolator, \
-    BilinearFieldInterpolator, \
-    TrilinearFieldInterpolator
+from yt.utilities.linear_interpolators import (
+    BilinearFieldInterpolator,
+    TrilinearFieldInterpolator,
+    UnilinearFieldInterpolator,
+)
 
 _int_class = {1: UnilinearFieldInterpolator,
               2: BilinearFieldInterpolator,
@@ -29,4 +29,3 @@ def _interpolated_field(field, data):
               function=_interpolated_field,
               units=units,
               validators=validators, particle_type=particle_type)
-              
diff --git a/yt/fields/local_fields.py b/yt/fields/local_fields.py
index 2a98b3e3c15..e26ff4da6a5 100644
--- a/yt/fields/local_fields.py
+++ b/yt/fields/local_fields.py
@@ -1,13 +1,10 @@
 import warnings
 
-from yt.utilities.logger import \
-    ytLogger as mylog
+from yt.utilities.logger import ytLogger as mylog
 
-from .field_plugin_registry import \
-    register_field_plugin
+from .field_info_container import FieldInfoContainer
+from .field_plugin_registry import register_field_plugin
 
-from .field_info_container import \
-    FieldInfoContainer
 
 class LocalFieldInfoContainer(FieldInfoContainer):
     def add_field(self, name, function=None, sampling_type=None, **kwargs):
diff --git a/yt/fields/magnetic_field.py b/yt/fields/magnetic_field.py
index d776a6929dc..0288b264d15 100644
--- a/yt/fields/magnetic_field.py
+++ b/yt/fields/magnetic_field.py
@@ -1,17 +1,12 @@
 import numpy as np
 
+from yt.fields.derived_field import ValidateParameter
 from yt.units import dimensions
 from yt.units.yt_array import ustack
+from yt.utilities.math_utils import get_sph_phi_component, get_sph_theta_component
 
-from yt.fields.derived_field import \
-    ValidateParameter
+from .field_plugin_registry import register_field_plugin
 
-from .field_plugin_registry import \
-    register_field_plugin
-
-from yt.utilities.math_utils import \
-    get_sph_theta_component, \
-    get_sph_phi_component
 
 @register_field_plugin
 def setup_magnetic_field_fields(registry, ftype="gas", slice_info=None):
diff --git a/yt/fields/my_plugin_fields.py b/yt/fields/my_plugin_fields.py
index 31e144e12e1..f3cd611777e 100644
--- a/yt/fields/my_plugin_fields.py
+++ b/yt/fields/my_plugin_fields.py
@@ -1,8 +1,5 @@
-from .field_plugin_registry import \
-    register_field_plugin
-
-from .local_fields import \
-    LocalFieldInfoContainer
+from .field_plugin_registry import register_field_plugin
+from .local_fields import LocalFieldInfoContainer
 
 # Empty FieldInfoContainer
 my_plugins_fields = LocalFieldInfoContainer(None, [], None)
diff --git a/yt/fields/particle_fields.py b/yt/fields/particle_fields.py
index 3f731614262..3244c2f716e 100644
--- a/yt/fields/particle_fields.py
+++ b/yt/fields/particle_fields.py
@@ -1,40 +1,30 @@
 import numpy as np
 
-from yt.fields.derived_field import \
-    ValidateParameter, \
-    ValidateSpatial
-
-from yt.fields.field_detector import \
-    FieldDetector
-
-from yt.funcs import \
-    issue_deprecation_warning
-
-from yt.units.yt_array import \
-    uconcatenate, \
-    ucross
-
-from yt.utilities.math_utils import \
-    get_sph_r_component, \
-    get_sph_theta_component, \
-    get_sph_phi_component, \
-    get_cyl_r_component, \
-    get_cyl_z_component, \
-    get_cyl_theta_component, \
-    get_cyl_r, get_cyl_theta, \
-    get_cyl_z, \
-    get_sph_theta, get_sph_phi, \
-    modify_reference_frame
-
-from yt.utilities.lib.misc_utilities import \
-    obtain_relative_velocity_vector, \
-    obtain_position_vector
-
-from .vector_operations import \
-    create_magnitude_field
-
-from .field_functions import \
-    get_radius
+from yt.fields.derived_field import ValidateParameter, ValidateSpatial
+from yt.fields.field_detector import FieldDetector
+from yt.funcs import issue_deprecation_warning
+from yt.units.yt_array import uconcatenate, ucross
+from yt.utilities.lib.misc_utilities import (
+    obtain_position_vector,
+    obtain_relative_velocity_vector,
+)
+from yt.utilities.math_utils import (
+    get_cyl_r,
+    get_cyl_r_component,
+    get_cyl_theta,
+    get_cyl_theta_component,
+    get_cyl_z,
+    get_cyl_z_component,
+    get_sph_phi,
+    get_sph_phi_component,
+    get_sph_r_component,
+    get_sph_theta,
+    get_sph_theta_component,
+    modify_reference_frame,
+)
+
+from .field_functions import get_radius
+from .vector_operations import create_magnitude_field
 
 sph_whitelist_fields = (
     'density',
diff --git a/yt/fields/species_fields.py b/yt/fields/species_fields.py
index 5fb5d4dedf7..de69e0c83fb 100644
--- a/yt/fields/species_fields.py
+++ b/yt/fields/species_fields.py
@@ -1,19 +1,14 @@
-import numpy as np
 import re
 
-from yt.fields.field_detector import \
-    FieldDetector
-from yt.frontends.sph.data_structures import \
-    ParticleDataset
-from yt.funcs import \
-    issue_deprecation_warning
-from yt.utilities.physical_ratios import \
-    _primordial_mass_fraction
-from yt.utilities.chemical_formulas import \
-    ChemicalFormula
-from .field_plugin_registry import \
-    register_field_plugin
+import numpy as np
+
+from yt.fields.field_detector import FieldDetector
+from yt.frontends.sph.data_structures import ParticleDataset
+from yt.funcs import issue_deprecation_warning
+from yt.utilities.chemical_formulas import ChemicalFormula
+from yt.utilities.physical_ratios import _primordial_mass_fraction
 
+from .field_plugin_registry import register_field_plugin
 
 # See YTEP-0003 for details, but we want to ensure these fields are all
 # populated:
diff --git a/yt/fields/tests/test_angular_momentum.py b/yt/fields/tests/test_angular_momentum.py
index 0d52afbd589..90450c0f062 100644
--- a/yt/fields/tests/test_angular_momentum.py
+++ b/yt/fields/tests/test_angular_momentum.py
@@ -1,8 +1,7 @@
 import numpy as np
 
-from yt.testing import \
-    assert_allclose_units, \
-    fake_amr_ds
+from yt.testing import assert_allclose_units, fake_amr_ds
+
 
 def test_AM_value():
     ds = fake_amr_ds(fields=("Density", "velocity_x", "velocity_y", "velocity_z"), length_unit=0.5)
diff --git a/yt/fields/tests/test_field_access.py b/yt/fields/tests/test_field_access.py
index d94e65daa28..2c275f1e7e9 100644
--- a/yt/fields/tests/test_field_access.py
+++ b/yt/fields/tests/test_field_access.py
@@ -1,12 +1,12 @@
-from yt.testing import fake_random_ds, assert_equal
 from yt.data_objects.profiles import create_profile
-from yt.visualization.plot_window import \
-    SlicePlot, \
-    ProjectionPlot, \
-    OffAxisProjectionPlot
-from yt.visualization.profile_plotter import \
-    ProfilePlot, \
-    PhasePlot
+from yt.testing import assert_equal, fake_random_ds
+from yt.visualization.plot_window import (
+    OffAxisProjectionPlot,
+    ProjectionPlot,
+    SlicePlot,
+)
+from yt.visualization.profile_plotter import PhasePlot, ProfilePlot
+
 
 def test_field_access():
     ds = fake_random_ds(16)
diff --git a/yt/fields/tests/test_field_name_container.py b/yt/fields/tests/test_field_name_container.py
index 0eddb7693d2..69dbc08bff9 100644
--- a/yt/fields/tests/test_field_name_container.py
+++ b/yt/fields/tests/test_field_name_container.py
@@ -1,7 +1,6 @@
-from yt import \
-    load
-from yt.testing import \
-    requires_file
+from yt import load
+from yt.testing import requires_file
+
 
 def do_field_type(ft):
     assert (dir(ft) == sorted(dir(ft)))
diff --git a/yt/fields/tests/test_fields.py b/yt/fields/tests/test_fields.py
index 3643c77477f..1af85a9383a 100644
--- a/yt/fields/tests/test_fields.py
+++ b/yt/fields/tests/test_fields.py
@@ -1,29 +1,27 @@
 import numpy as np
 
-from yt import \
-    load
-from yt.testing import \
-    fake_amr_ds, \
-    fake_random_ds, \
-    fake_particle_ds, \
-    assert_almost_equal, \
-    assert_equal, \
-    assert_array_almost_equal_nulp, \
-    assert_array_equal, \
-    assert_raises, \
-    assert_allclose_units, \
-    requires_file
-from yt.utilities.cosmology import \
-    Cosmology
-from yt.frontends.stream.fields import \
-    StreamFieldInfo
-from yt.units.yt_array import \
-    array_like_field, \
-    YTArray, YTQuantity
-from yt.utilities.exceptions import \
-    YTFieldUnitError, \
-    YTFieldUnitParseError, \
-    YTDimensionalityError
+from yt import load
+from yt.frontends.stream.fields import StreamFieldInfo
+from yt.testing import (
+    assert_allclose_units,
+    assert_almost_equal,
+    assert_array_almost_equal_nulp,
+    assert_array_equal,
+    assert_equal,
+    assert_raises,
+    fake_amr_ds,
+    fake_particle_ds,
+    fake_random_ds,
+    requires_file,
+)
+from yt.units.yt_array import YTArray, YTQuantity, array_like_field
+from yt.utilities.cosmology import Cosmology
+from yt.utilities.exceptions import (
+    YTDimensionalityError,
+    YTFieldUnitError,
+    YTFieldUnitParseError,
+)
+
 
 def get_params(ds):
     return dict(
@@ -431,4 +429,3 @@ def test_ion_field_labels():
     for f in fields:
         label = getattr(fobj, f).get_latex_display_name()
         assert_equal(label, pm_labels[f])
-
diff --git a/yt/fields/tests/test_fields_plugins.py b/yt/fields/tests/test_fields_plugins.py
index d59e78ea8b1..5b9f76268b3 100644
--- a/yt/fields/tests/test_fields_plugins.py
+++ b/yt/fields/tests/test_fields_plugins.py
@@ -1,11 +1,10 @@
 import os
 import sys
 import unittest
+
 import yt
-from yt.config import ytcfg, CONFIG_DIR
-from yt.testing import \
-    assert_raises, \
-    fake_random_ds
+from yt.config import CONFIG_DIR, ytcfg
+from yt.testing import assert_raises, fake_random_ds
 
 TEST_PLUGIN_FILE = '''
 def _myfunc(field, data):
diff --git a/yt/fields/tests/test_magnetic_fields.py b/yt/fields/tests/test_magnetic_fields.py
index 56b3dbc66c7..e902d0adadb 100644
--- a/yt/fields/tests/test_magnetic_fields.py
+++ b/yt/fields/tests/test_magnetic_fields.py
@@ -1,7 +1,9 @@
 import numpy as np
-from yt.utilities.physical_constants import mu_0
-from yt.testing import assert_almost_equal
+
 from yt.frontends.stream.api import load_uniform_grid
+from yt.testing import assert_almost_equal
+from yt.utilities.physical_constants import mu_0
+
 
 def setup():
     from yt.config import ytcfg
diff --git a/yt/fields/tests/test_particle_fields.py b/yt/fields/tests/test_particle_fields.py
index 91885189aad..d3610c8522a 100644
--- a/yt/fields/tests/test_particle_fields.py
+++ b/yt/fields/tests/test_particle_fields.py
@@ -1,8 +1,5 @@
-from yt.testing import \
-    assert_allclose_units, \
-    requires_file
-from yt.utilities.answer_testing.framework import \
-    data_dir_load
+from yt.testing import assert_allclose_units, requires_file
+from yt.utilities.answer_testing.framework import data_dir_load
 
 g30 = "IsolatedGalaxy/galaxy0030/galaxy0030"
 @requires_file(g30)
diff --git a/yt/fields/tests/test_species_fields.py b/yt/fields/tests/test_species_fields.py
index 59ad4150c82..0a419b1f30b 100644
--- a/yt/fields/tests/test_species_fields.py
+++ b/yt/fields/tests/test_species_fields.py
@@ -1,11 +1,7 @@
-from yt.testing import requires_file, \
-    assert_allclose_units, assert_equal
-from yt.utilities.answer_testing.framework import \
-    data_dir_load
-from yt.utilities.physical_ratios import \
-    _primordial_mass_fraction
-from yt.utilities.chemical_formulas import \
-    ChemicalFormula
+from yt.testing import assert_allclose_units, assert_equal, requires_file
+from yt.utilities.answer_testing.framework import data_dir_load
+from yt.utilities.chemical_formulas import ChemicalFormula
+from yt.utilities.physical_ratios import _primordial_mass_fraction
 
 sloshing = "GasSloshing/sloshing_nomag2_hdf5_plt_cnt_0100"
 
diff --git a/yt/fields/tests/test_sph_fields.py b/yt/fields/tests/test_sph_fields.py
index d039c434cc7..55efabd25ce 100644
--- a/yt/fields/tests/test_sph_fields.py
+++ b/yt/fields/tests/test_sph_fields.py
@@ -1,10 +1,7 @@
-import yt
-
 from collections import defaultdict
-from yt.testing import \
-    assert_array_almost_equal, \
-    assert_equal, \
-    requires_file
+
+import yt
+from yt.testing import assert_array_almost_equal, assert_equal, requires_file
 
 isothermal_h5 = "IsothermalCollapse/snap_505.hdf5"
 isothermal_bin = "IsothermalCollapse/snap_505"
diff --git a/yt/fields/tests/test_vector_fields.py b/yt/fields/tests/test_vector_fields.py
index 75e41e1bfa7..f9fcae69ad1 100644
--- a/yt/fields/tests/test_vector_fields.py
+++ b/yt/fields/tests/test_vector_fields.py
@@ -1,12 +1,9 @@
 import numpy as np
 
-from yt.testing import \
-    assert_allclose_units, \
-    fake_random_ds, \
-    requires_file
-from yt.utilities.answer_testing.framework import \
-    data_dir_load
+from yt.testing import assert_allclose_units, fake_random_ds, requires_file
 from yt.units import cm, s
+from yt.utilities.answer_testing.framework import data_dir_load
+
 
 def random_unit_vector(prng):
     v = prng.random_sample(3)
diff --git a/yt/fields/tests/test_xray_fields.py b/yt/fields/tests/test_xray_fields.py
index 2401d385efa..9fb2d6045fe 100644
--- a/yt/fields/tests/test_xray_fields.py
+++ b/yt/fields/tests/test_xray_fields.py
@@ -1,8 +1,11 @@
-from yt.fields.xray_emission_fields import \
-    add_xray_emissivity_field
-from yt.utilities.answer_testing.framework import \
-    requires_ds, can_run_ds, data_dir_load, \
-    ProjectionValuesTest, FieldValuesTest
+from yt.fields.xray_emission_fields import add_xray_emissivity_field
+from yt.utilities.answer_testing.framework import (
+    FieldValuesTest,
+    ProjectionValuesTest,
+    can_run_ds,
+    data_dir_load,
+    requires_ds,
+)
 
 
 def setup():
diff --git a/yt/fields/vector_operations.py b/yt/fields/vector_operations.py
index 98b2fdf0531..a82f41052d4 100644
--- a/yt/fields/vector_operations.py
+++ b/yt/fields/vector_operations.py
@@ -1,24 +1,19 @@
 import numpy as np
 
-from .derived_field import \
-    ValidateParameter, \
-    ValidateSpatial, \
-    NeedsParameter
-
-from yt.utilities.math_utils import \
-    get_sph_r_component, \
-    get_sph_theta_component, \
-    get_sph_phi_component, \
-    get_cyl_r_component, \
-    get_cyl_z_component, \
-    get_cyl_theta_component
-
-from yt.funcs import just_one, iterable
+from yt.funcs import iterable, just_one
+from yt.geometry.geometry_handler import is_curvilinear
+from yt.utilities.lib.misc_utilities import obtain_relative_velocity_vector
+from yt.utilities.math_utils import (
+    get_cyl_r_component,
+    get_cyl_theta_component,
+    get_cyl_z_component,
+    get_sph_phi_component,
+    get_sph_r_component,
+    get_sph_theta_component,
+)
 
-from yt.geometry.geometry_handler import \
-    is_curvilinear
+from .derived_field import NeedsParameter, ValidateParameter, ValidateSpatial
 
-from yt.utilities.lib.misc_utilities import obtain_relative_velocity_vector
 
 def get_bulk(data, basename, unit):
     if data.has_field_parameter("bulk_%s" % basename):
diff --git a/yt/fields/xray_emission_fields.py b/yt/fields/xray_emission_fields.py
index a8c7d837a28..28b0084ea42 100644
--- a/yt/fields/xray_emission_fields.py
+++ b/yt/fields/xray_emission_fields.py
@@ -1,19 +1,18 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
-import numpy as np
 import os
 
+import numpy as np
+
 from yt.config import ytcfg
 from yt.fields.derived_field import DerivedField
-from yt.funcs import \
-    mylog, \
-    only_on_root, \
-    parse_h5_attr
-from yt.utilities.exceptions import YTFieldNotFound
-from yt.utilities.exceptions import YTException
-from yt.utilities.linear_interpolators import \
-    UnilinearFieldInterpolator, BilinearFieldInterpolator
+from yt.funcs import mylog, only_on_root, parse_h5_attr
 from yt.units.yt_array import YTArray, YTQuantity
 from yt.utilities.cosmology import Cosmology
+from yt.utilities.exceptions import YTException, YTFieldNotFound
+from yt.utilities.linear_interpolators import (
+    BilinearFieldInterpolator,
+    UnilinearFieldInterpolator,
+)
+from yt.utilities.on_demand_imports import _h5py as h5py
 
 data_version = {"cloudy": 2,
                 "apec": 3}
diff --git a/yt/frontends/_skeleton/__init__.py b/yt/frontends/_skeleton/__init__.py
index c8a618b340d..82efc2971eb 100644
--- a/yt/frontends/_skeleton/__init__.py
+++ b/yt/frontends/_skeleton/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/_skeleton/api.py b/yt/frontends/_skeleton/api.py
index fb890486926..1ed213e47b8 100644
--- a/yt/frontends/_skeleton/api.py
+++ b/yt/frontends/_skeleton/api.py
@@ -1,10 +1,3 @@
-from .data_structures import \
-      SkeletonGrid, \
-      SkeletonHierarchy, \
-      SkeletonDataset
-
-from .fields import \
-      SkeletonFieldInfo
-
-from .io import \
-      SkeletonIOHandler
+from .data_structures import SkeletonDataset, SkeletonGrid, SkeletonHierarchy
+from .fields import SkeletonFieldInfo
+from .io import SkeletonIOHandler
diff --git a/yt/frontends/_skeleton/data_structures.py b/yt/frontends/_skeleton/data_structures.py
index 60e6ebbec2f..cb295525677 100644
--- a/yt/frontends/_skeleton/data_structures.py
+++ b/yt/frontends/_skeleton/data_structures.py
@@ -1,13 +1,12 @@
 import os
-import numpy as np
 import weakref
 
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.data_objects.static_output import \
-    Dataset
+import numpy as np
+
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset
+from yt.geometry.grid_geometry_handler import GridIndex
+
 from .fields import SkeletonFieldInfo
 
 
diff --git a/yt/frontends/_skeleton/fields.py b/yt/frontends/_skeleton/fields.py
index 684bebc0dd6..8a95ef61fb8 100644
--- a/yt/frontends/_skeleton/fields.py
+++ b/yt/frontends/_skeleton/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 # We need to specify which fields we might have in our dataset.  The field info
 # container subclass here will define which fields it knows about.  There are
diff --git a/yt/frontends/_skeleton/io.py b/yt/frontends/_skeleton/io.py
index 22a91c6b813..f1600163a35 100644
--- a/yt/frontends/_skeleton/io.py
+++ b/yt/frontends/_skeleton/io.py
@@ -1,5 +1,4 @@
-from yt.utilities.io_handler import \
-    BaseIOHandler
+from yt.utilities.io_handler import BaseIOHandler
 
 
 class SkeletonIOHandler(BaseIOHandler):
diff --git a/yt/frontends/adaptahop/api.py b/yt/frontends/adaptahop/api.py
index 6eeafac327b..85e84001ba1 100644
--- a/yt/frontends/adaptahop/api.py
+++ b/yt/frontends/adaptahop/api.py
@@ -14,13 +14,7 @@
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
-from .data_structures import \
-     AdaptaHOPDataset
-
-from .io import \
-     IOHandlerAdaptaHOPBinary
-
-from .fields import \
-     AdaptaHOPFieldInfo
-
 from . import tests
+from .data_structures import AdaptaHOPDataset
+from .fields import AdaptaHOPFieldInfo
+from .io import IOHandlerAdaptaHOPBinary
diff --git a/yt/frontends/adaptahop/data_structures.py b/yt/frontends/adaptahop/data_structures.py
index acd71163a76..ae788d960ed 100644
--- a/yt/frontends/adaptahop/data_structures.py
+++ b/yt/frontends/adaptahop/data_structures.py
@@ -14,26 +14,24 @@
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
-import numpy as np
-import stat
 import os
 import re
+import stat
 
-from yt.data_objects.data_containers import \
-    YTSelectionContainer
-from yt.data_objects.static_output import \
-    Dataset
-from yt.frontends.halo_catalog.data_structures import \
-    HaloCatalogFile, HaloCatalogParticleIndex
-from yt.funcs import \
-    setdefaultattr
-from yt.utilities.cython_fortran_utils import FortranFile
+import numpy as np
+
+from yt.data_objects.data_containers import YTSelectionContainer
+from yt.data_objects.static_output import Dataset
+from yt.frontends.halo_catalog.data_structures import (
+    HaloCatalogFile,
+    HaloCatalogParticleIndex,
+)
+from yt.funcs import setdefaultattr
 from yt.units import Mpc
+from yt.utilities.cython_fortran_utils import FortranFile
 
-from .definitions import \
-    HEADER_ATTRIBUTES
-from .fields import \
-    AdaptaHOPFieldInfo
+from .definitions import HEADER_ATTRIBUTES
+from .fields import AdaptaHOPFieldInfo
 
 
 class AdaptaHOPDataset(Dataset):
diff --git a/yt/frontends/adaptahop/fields.py b/yt/frontends/adaptahop/fields.py
index 6c2bd71d46e..be2f6a932d8 100644
--- a/yt/frontends/adaptahop/fields.py
+++ b/yt/frontends/adaptahop/fields.py
@@ -14,8 +14,7 @@
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 m_units = "1e11 * Msun"
 r_units = "Mpc"
diff --git a/yt/frontends/adaptahop/io.py b/yt/frontends/adaptahop/io.py
index fd17aedd10f..d85a5241121 100644
--- a/yt/frontends/adaptahop/io.py
+++ b/yt/frontends/adaptahop/io.py
@@ -14,23 +14,18 @@
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
+from operator import attrgetter
+
 import numpy as np
 
 from yt.funcs import mylog
-
-from yt.utilities.exceptions import \
-    YTDomainOverflow
-
-from yt.utilities.io_handler import \
-    BaseIOHandler
-
-from yt.utilities.lib.geometry_utils import compute_morton
 from yt.utilities.cython_fortran_utils import FortranFile
+from yt.utilities.exceptions import YTDomainOverflow
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.lib.geometry_utils import compute_morton
 
-from operator import attrgetter
+from .definitions import HALO_ATTRIBUTES, HEADER_ATTRIBUTES
 
-from .definitions import \
-    HEADER_ATTRIBUTES, HALO_ATTRIBUTES
 
 class IOHandlerAdaptaHOPBinary(BaseIOHandler):
     _dataset_type = "adaptahop_binary"
diff --git a/yt/frontends/adaptahop/tests/test_outputs.py b/yt/frontends/adaptahop/tests/test_outputs.py
index de84ae93e1c..e68541ad58e 100644
--- a/yt/frontends/adaptahop/tests/test_outputs.py
+++ b/yt/frontends/adaptahop/tests/test_outputs.py
@@ -15,11 +15,9 @@
 
 import numpy as np
 
-from yt.testing import requires_file
-from yt.utilities.answer_testing.framework import \
-    data_dir_load
-
 from yt.frontends.adaptahop.data_structures import AdaptaHOPDataset
+from yt.testing import requires_file
+from yt.utilities.answer_testing.framework import data_dir_load
 
 r0 = "output_00080/info_00080.txt"
 r1 = "output_00080_halos/tree_bricks080"
diff --git a/yt/frontends/ahf/__init__.py b/yt/frontends/ahf/__init__.py
index 45cf0d77321..6dcd0757862 100644
--- a/yt/frontends/ahf/__init__.py
+++ b/yt/frontends/ahf/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/ahf/api.py b/yt/frontends/ahf/api.py
index 2326c273921..d8b3e3b0d4c 100644
--- a/yt/frontends/ahf/api.py
+++ b/yt/frontends/ahf/api.py
@@ -1,8 +1,3 @@
-from .data_structures import \
-      AHFHalosDataset
-
-from .fields import \
-      AHFHalosFieldInfo
-
-from .io import \
-      IOHandlerAHFHalos
+from .data_structures import AHFHalosDataset
+from .fields import AHFHalosFieldInfo
+from .io import IOHandlerAHFHalos
diff --git a/yt/frontends/ahf/data_structures.py b/yt/frontends/ahf/data_structures.py
index 2ba725291a6..5e568efed0f 100644
--- a/yt/frontends/ahf/data_structures.py
+++ b/yt/frontends/ahf/data_structures.py
@@ -3,16 +3,11 @@
 
 import numpy as np
 
-from yt.data_objects.static_output import \
-    Dataset
-from yt.frontends.halo_catalog.data_structures import \
-    HaloCatalogFile
-from yt.funcs import \
-    setdefaultattr
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
-from yt.utilities.cosmology import \
-    Cosmology
+from yt.data_objects.static_output import Dataset
+from yt.frontends.halo_catalog.data_structures import HaloCatalogFile
+from yt.funcs import setdefaultattr
+from yt.geometry.particle_geometry_handler import ParticleIndex
+from yt.utilities.cosmology import Cosmology
 
 from .fields import AHFHalosFieldInfo
 
diff --git a/yt/frontends/ahf/fields.py b/yt/frontends/ahf/fields.py
index 7277f140586..3b086c84eb6 100644
--- a/yt/frontends/ahf/fields.py
+++ b/yt/frontends/ahf/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 m_units = 'Msun/h'
 p_units = 'kpccm/h'
diff --git a/yt/frontends/ahf/io.py b/yt/frontends/ahf/io.py
index 098ad52f76f..1561f1f1fb1 100644
--- a/yt/frontends/ahf/io.py
+++ b/yt/frontends/ahf/io.py
@@ -2,14 +2,10 @@
 
 import numpy as np
 
-from yt.funcs import \
-    mylog
-from yt.utilities.exceptions import \
-    YTDomainOverflow
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.utilities.lib.geometry_utils import \
-    compute_morton
+from yt.funcs import mylog
+from yt.utilities.exceptions import YTDomainOverflow
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.lib.geometry_utils import compute_morton
 
 
 class IOHandlerAHFHalos(BaseIOHandler):
diff --git a/yt/frontends/ahf/tests/test_outputs.py b/yt/frontends/ahf/tests/test_outputs.py
index 7d3cdee61e5..dbec5febe4d 100644
--- a/yt/frontends/ahf/tests/test_outputs.py
+++ b/yt/frontends/ahf/tests/test_outputs.py
@@ -1,13 +1,12 @@
 import os.path
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    ParticleSelectionComparison
-from yt.utilities.answer_testing.framework import \
-    FieldValuesTest, \
-    requires_ds, \
-    data_dir_load
+
 from yt.frontends.ahf.api import AHFHalosDataset
+from yt.testing import ParticleSelectionComparison, assert_equal, requires_file
+from yt.utilities.answer_testing.framework import (
+    FieldValuesTest,
+    data_dir_load,
+    requires_ds,
+)
 
 _fields = ('particle_position_x', 'particle_position_y',
            'particle_position_z', 'particle_mass')
diff --git a/yt/frontends/amrvac/__init__.py b/yt/frontends/amrvac/__init__.py
index 1c69b8b9233..ec25700a0aa 100644
--- a/yt/frontends/amrvac/__init__.py
+++ b/yt/frontends/amrvac/__init__.py
@@ -15,6 +15,7 @@
 
 from yt.utilities.on_demand_imports import _f90nml as f90nml
 
+
 def read_amrvac_namelist(parfiles):
     """Read one or more parfiles, and return a unified f90nml.Namelist object.
 
diff --git a/yt/frontends/amrvac/api.py b/yt/frontends/amrvac/api.py
index 5d5f9afa897..cf42eff628f 100644
--- a/yt/frontends/amrvac/api.py
+++ b/yt/frontends/amrvac/api.py
@@ -13,13 +13,6 @@
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
-from .data_structures import \
-      AMRVACGrid, \
-      AMRVACHierarchy, \
-      AMRVACDataset
-
-from .fields import \
-      AMRVACFieldInfo
-
-from .io import \
-      AMRVACIOHandler
+from .data_structures import AMRVACDataset, AMRVACGrid, AMRVACHierarchy
+from .fields import AMRVACFieldInfo
+from .io import AMRVACIOHandler
diff --git a/yt/frontends/amrvac/data_structures.py b/yt/frontends/amrvac/data_structures.py
index b7ec5369e37..befd6ffc3b8 100644
--- a/yt/frontends/amrvac/data_structures.py
+++ b/yt/frontends/amrvac/data_structures.py
@@ -15,26 +15,20 @@
 
 import os
 import stat
-import weakref
 import struct
+import weakref
 
 import numpy as np
 
-from yt.data_objects.grid_patch import \
-   AMRGridPatch
-from yt.geometry.grid_geometry_handler import \
-   GridIndex
-from yt.funcs import \
-    mylog, \
-    setdefaultattr
-from yt.data_objects.static_output import \
-   Dataset
-from yt.utilities.physical_constants import \
-    boltzmann_constant_cgs as kb_cgs
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset
+from yt.funcs import mylog, setdefaultattr
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.utilities.physical_constants import boltzmann_constant_cgs as kb_cgs
 
-from .fields import AMRVACFieldInfo
-from .datfile_utils import get_header, get_tree_info
 from . import read_amrvac_namelist
+from .datfile_utils import get_header, get_tree_info
+from .fields import AMRVACFieldInfo
 
 ALLOWED_UNIT_COMBINATIONS = [{'numberdensity_unit', 'temperature_unit', 'length_unit'},
                              {'mass_unit', 'temperature_unit', 'length_unit'},
diff --git a/yt/frontends/amrvac/datfile_utils.py b/yt/frontends/amrvac/datfile_utils.py
index d1b3516f0b2..02b9fb783cc 100644
--- a/yt/frontends/amrvac/datfile_utils.py
+++ b/yt/frontends/amrvac/datfile_utils.py
@@ -1,4 +1,5 @@
 import struct
+
 import numpy as np
 
 # Size of basic types (in bytes)
diff --git a/yt/frontends/amrvac/fields.py b/yt/frontends/amrvac/fields.py
index cfbd7c3b355..98e866415eb 100644
--- a/yt/frontends/amrvac/fields.py
+++ b/yt/frontends/amrvac/fields.py
@@ -12,12 +12,13 @@
 #-----------------------------------------------------------------------------
 
 import functools
+
 import numpy as np
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+
+from yt import mylog
+from yt.fields.field_info_container import FieldInfoContainer
 from yt.fields.magnetic_field import setup_magnetic_field_aliases
 from yt.units import dimensions
-from yt import mylog
 
 # We need to specify which fields we might have in our dataset.  The field info
 # container subclass here will define which fields it knows about.  There are
diff --git a/yt/frontends/amrvac/io.py b/yt/frontends/amrvac/io.py
index 74764cfd2e5..c916f148d95 100644
--- a/yt/frontends/amrvac/io.py
+++ b/yt/frontends/amrvac/io.py
@@ -13,10 +13,10 @@
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 import numpy as np
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.geometry.selection_routines import \
-    GridSelector
+
+from yt.geometry.selection_routines import GridSelector
+from yt.utilities.io_handler import BaseIOHandler
+
 from .datfile_utils import get_single_block_field_data
 
 
diff --git a/yt/frontends/amrvac/tests/test_outputs.py b/yt/frontends/amrvac/tests/test_outputs.py
index 2ccad3ed614..08ca7fc401a 100644
--- a/yt/frontends/amrvac/tests/test_outputs.py
+++ b/yt/frontends/amrvac/tests/test_outputs.py
@@ -1,14 +1,14 @@
-import numpy as np # NOQA
-
-import yt # NOQA
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load, small_patch_amr
-from yt.testing import requires_file, \
-    assert_allclose_units, \
-    assert_raises
+import numpy as np  # NOQA
+
+import yt  # NOQA
 from yt.frontends.amrvac.api import AMRVACDataset, AMRVACGrid
+from yt.testing import assert_allclose_units, assert_raises, requires_file
 from yt.units import YTQuantity
+from yt.utilities.answer_testing.framework import (
+    data_dir_load,
+    requires_ds,
+    small_patch_amr,
+)
 
 blastwave_spherical_2D = "amrvac/bw_2d0000.dat"
 khi_cartesian_2D = "amrvac/kh_2d0000.dat"
diff --git a/yt/frontends/amrvac/tests/test_read_amrvac_namelist.py b/yt/frontends/amrvac/tests/test_read_amrvac_namelist.py
index 46364a89c83..fb41d33653f 100644
--- a/yt/frontends/amrvac/tests/test_read_amrvac_namelist.py
+++ b/yt/frontends/amrvac/tests/test_read_amrvac_namelist.py
@@ -1,8 +1,9 @@
-from os import path
 from copy import deepcopy
+from os import path
+
+from yt.frontends.amrvac import read_amrvac_namelist
 from yt.testing import requires_module
 from yt.utilities.on_demand_imports import _f90nml as f90nml
-from yt.frontends.amrvac import read_amrvac_namelist
 
 test_dir = path.dirname(path.abspath(__file__))
 blast_wave_parfile = path.join(test_dir, "sample_parfiles/bw_3d.par")
diff --git a/yt/frontends/api.py b/yt/frontends/api.py
index 46d8967b5b2..6c334a1b6c2 100644
--- a/yt/frontends/api.py
+++ b/yt/frontends/api.py
@@ -1,4 +1,9 @@
-import sys, types, os, glob, time, importlib
+import glob
+import importlib
+import os
+import sys
+import time
+import types
 
 _frontends = [
     'adaptahop',
diff --git a/yt/frontends/arepo/api.py b/yt/frontends/arepo/api.py
index fdd4405e77f..5d92414c9af 100644
--- a/yt/frontends/arepo/api.py
+++ b/yt/frontends/arepo/api.py
@@ -1,8 +1,3 @@
-from .data_structures import \
-    ArepoHDF5Dataset, \
-    ArepoFieldInfo
-
-from .io import \
-    IOHandlerArepoHDF5
-
 from . import tests
+from .data_structures import ArepoFieldInfo, ArepoHDF5Dataset
+from .io import IOHandlerArepoHDF5
diff --git a/yt/frontends/arepo/data_structures.py b/yt/frontends/arepo/data_structures.py
index a9ea881a853..039d015ab60 100644
--- a/yt/frontends/arepo/data_structures.py
+++ b/yt/frontends/arepo/data_structures.py
@@ -1,11 +1,10 @@
+import numpy as np
+
 from yt.frontends.gadget.api import GadgetHDF5Dataset
 from yt.funcs import mylog
 from yt.utilities.on_demand_imports import _h5py as h5py
 
-from .fields import \
-    ArepoFieldInfo
-
-import numpy as np
+from .fields import ArepoFieldInfo
 
 
 class ArepoHDF5Dataset(GadgetHDF5Dataset):
diff --git a/yt/frontends/arepo/fields.py b/yt/frontends/arepo/fields.py
index fd43b69f57b..900f097d579 100644
--- a/yt/frontends/arepo/fields.py
+++ b/yt/frontends/arepo/fields.py
@@ -1,11 +1,7 @@
+from yt.fields.field_info_container import FieldInfoContainer
+from yt.fields.magnetic_field import setup_magnetic_field_aliases
+from yt.fields.species_fields import add_species_field_by_fraction, setup_species_fields
 from yt.frontends.gadget.api import GadgetFieldInfo
-from yt.fields.magnetic_field import \
-    setup_magnetic_field_aliases
-from yt.fields.species_fields import \
-    add_species_field_by_fraction, \
-    setup_species_fields
-from yt.fields.field_info_container import \
-    FieldInfoContainer
 
 metal_elements = ["He", "C", "N", "O", "Ne",
                   "Mg", "Si", "Fe"]
diff --git a/yt/frontends/arepo/io.py b/yt/frontends/arepo/io.py
index b0af0f90b83..0914e4625d1 100644
--- a/yt/frontends/arepo/io.py
+++ b/yt/frontends/arepo/io.py
@@ -1,7 +1,9 @@
-from yt.frontends.gadget.api import IOHandlerGadgetHDF5
 import numpy as np
+
+from yt.frontends.gadget.api import IOHandlerGadgetHDF5
 from yt.utilities.on_demand_imports import _h5py as h5py
 
+
 class IOHandlerArepoHDF5(IOHandlerGadgetHDF5):
     _dataset_type = "arepo_hdf5"
 
@@ -30,4 +32,3 @@ def _identify_fields(self, data_file):
                                self)._identify_fields(data_file)
         fields.append(("PartType0", "smoothing_length"))
         return fields, _units
-
diff --git a/yt/frontends/arepo/tests/test_outputs.py b/yt/frontends/arepo/tests/test_outputs.py
index 2dd2197880a..711b962cd39 100644
--- a/yt/frontends/arepo/tests/test_outputs.py
+++ b/yt/frontends/arepo/tests/test_outputs.py
@@ -1,12 +1,10 @@
 import os
 import tempfile
 from collections import OrderedDict
-from yt.testing import requires_file, ParticleSelectionComparison
-from yt.utilities.answer_testing.framework import \
-    data_dir_load, \
-    requires_ds, \
-    sph_answer
+
 from yt.frontends.arepo.api import ArepoHDF5Dataset
+from yt.testing import ParticleSelectionComparison, requires_file
+from yt.utilities.answer_testing.framework import data_dir_load, requires_ds, sph_answer
 
 bullet_h5 = "ArepoBullet/snapshot_150.hdf5"
 tng59_h5 = "TNGHalo/halo_59.hdf5"
diff --git a/yt/frontends/art/__init__.py b/yt/frontends/art/__init__.py
index 8481d7b4d5f..551f529b794 100644
--- a/yt/frontends/art/__init__.py
+++ b/yt/frontends/art/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/art/api.py b/yt/frontends/art/api.py
index fe112a4e86e..56a8778cd78 100644
--- a/yt/frontends/art/api.py
+++ b/yt/frontends/art/api.py
@@ -1,14 +1,10 @@
-from .data_structures import \
-      ARTDomainFile,\
-      ARTDomainSubset,\
-      ARTIndex,\
-      ARTDataset, \
-      DarkMatterARTDataset
-
-from .fields import \
-      ARTFieldInfo
-
-from .io import \
-      IOHandlerART
-
 from . import tests
+from .data_structures import (
+    ARTDataset,
+    ARTDomainFile,
+    ARTDomainSubset,
+    ARTIndex,
+    DarkMatterARTDataset,
+)
+from .fields import ARTFieldInfo
+from .io import IOHandlerART
diff --git a/yt/frontends/art/data_structures.py b/yt/frontends/art/data_structures.py
index 039678466e3..781fb9452fe 100644
--- a/yt/frontends/art/data_structures.py
+++ b/yt/frontends/art/data_structures.py
@@ -1,44 +1,37 @@
 import glob
-import numpy as np
 import os
 import struct
 import weakref
 
-from yt.geometry.oct_geometry_handler import \
-    OctreeIndex
-from yt.geometry.geometry_handler import \
-    YTDataChunk
-from yt.data_objects.static_output import \
-    Dataset, ParticleFile
-from yt.data_objects.octree_subset import \
-    OctreeSubset
-from yt.funcs import \
-    mylog, \
-    setdefaultattr
-from yt.geometry.oct_container import \
-    ARTOctreeContainer
-from yt.frontends.art.definitions import \
-    fluid_fields, \
-    particle_fields, \
-    filename_pattern, \
-    particle_header_struct, \
-    amr_header_struct, \
-    dmparticle_header_struct, \
-    constants, \
-    seek_extras
-from yt.frontends.art.fields import ARTFieldInfo
-from yt.data_objects.particle_unions import \
-    ParticleUnion
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
+import numpy as np
 
 import yt.utilities.fortran_utils as fpu
-from yt.frontends.art.io import \
-    _read_art_level_info, \
-    _read_child_level, \
-    _read_root_level, \
-    b2t, \
-    a2b
+from yt.data_objects.octree_subset import OctreeSubset
+from yt.data_objects.particle_unions import ParticleUnion
+from yt.data_objects.static_output import Dataset, ParticleFile
+from yt.frontends.art.definitions import (
+    amr_header_struct,
+    constants,
+    dmparticle_header_struct,
+    filename_pattern,
+    fluid_fields,
+    particle_fields,
+    particle_header_struct,
+    seek_extras,
+)
+from yt.frontends.art.fields import ARTFieldInfo
+from yt.frontends.art.io import (
+    _read_art_level_info,
+    _read_child_level,
+    _read_root_level,
+    a2b,
+    b2t,
+)
+from yt.funcs import mylog, setdefaultattr
+from yt.geometry.geometry_handler import YTDataChunk
+from yt.geometry.oct_container import ARTOctreeContainer
+from yt.geometry.oct_geometry_handler import OctreeIndex
+from yt.geometry.particle_geometry_handler import ParticleIndex
 
 
 class ARTIndex(OctreeIndex):
diff --git a/yt/frontends/art/fields.py b/yt/frontends/art/fields.py
index 19712ab9493..1f5a3866b46 100644
--- a/yt/frontends/art/fields.py
+++ b/yt/frontends/art/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 b_units = "code_magnetic"
 ra_units = "code_length / code_time**2"
diff --git a/yt/frontends/art/io.py b/yt/frontends/art/io.py
index 74b4f3f6688..1998dba752e 100644
--- a/yt/frontends/art/io.py
+++ b/yt/frontends/art/io.py
@@ -1,29 +1,26 @@
 
-import numpy as np
 import os
 import os.path
 import sys
-
 from collections import defaultdict
 
+import numpy as np
+
+from yt.frontends.art.definitions import (
+    hydro_struct,
+    particle_fields,
+    particle_star_fields,
+    star_struct,
+)
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.fortran_utils import read_vector, skip
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.lib.geometry_utils import compute_morton
+from yt.utilities.logger import ytLogger as mylog
+
 if sys.version_info >= (3,0,0):
     long = int
 
-from yt.frontends.art.definitions import \
-    particle_star_fields, \
-    particle_fields, \
-    star_struct, \
-    hydro_struct
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.utilities.logger import ytLogger as mylog
-from yt.utilities.lib.geometry_utils import compute_morton
-from yt.utilities.fortran_utils import \
-    read_vector, \
-    skip
-from yt.units.yt_array import \
-    YTQuantity, \
-    YTArray
 
 class IOHandlerART(BaseIOHandler):
     _dataset_type = "art"
diff --git a/yt/frontends/art/tests/test_outputs.py b/yt/frontends/art/tests/test_outputs.py
index db2f9ac82d2..1a768c36fc4 100644
--- a/yt/frontends/art/tests/test_outputs.py
+++ b/yt/frontends/art/tests/test_outputs.py
@@ -1,17 +1,18 @@
-from yt.testing import \
-    requires_file, \
-    assert_equal, \
-    units_override_check, \
-    assert_almost_equal, \
-    ParticleSelectionComparison
-from yt.units.yt_array import \
-    YTQuantity
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    FieldValuesTest, \
-    PixelizedProjectionValuesTest, \
-    data_dir_load
 from yt.frontends.art.api import ARTDataset
+from yt.testing import (
+    ParticleSelectionComparison,
+    assert_almost_equal,
+    assert_equal,
+    requires_file,
+    units_override_check,
+)
+from yt.units.yt_array import YTQuantity
+from yt.utilities.answer_testing.framework import (
+    FieldValuesTest,
+    PixelizedProjectionValuesTest,
+    data_dir_load,
+    requires_ds,
+)
 
 _fields = (
     ("gas", "density"),
diff --git a/yt/frontends/artio/__init__.py b/yt/frontends/artio/__init__.py
index 17195075cf4..1812efd2c5c 100644
--- a/yt/frontends/artio/__init__.py
+++ b/yt/frontends/artio/__init__.py
@@ -5,4 +5,3 @@
 
 
 """
-
diff --git a/yt/frontends/artio/api.py b/yt/frontends/artio/api.py
index 2b0cf57443f..2e80b33ca36 100644
--- a/yt/frontends/artio/api.py
+++ b/yt/frontends/artio/api.py
@@ -1,10 +1,4 @@
-from .data_structures import \
-    ARTIODataset
-
-from .fields import \
-    ARTIOFieldInfo
-
-from .io import \
-    IOHandlerARTIO
-
 from . import tests
+from .data_structures import ARTIODataset
+from .fields import ARTIOFieldInfo
+from .io import IOHandlerARTIO
diff --git a/yt/frontends/artio/data_structures.py b/yt/frontends/artio/data_structures.py
index 144cc475785..eb42957c967 100644
--- a/yt/frontends/artio/data_structures.py
+++ b/yt/frontends/artio/data_structures.py
@@ -1,34 +1,25 @@
-import numpy as np
 import os
 import weakref
-
 from collections import defaultdict
 
-from yt.frontends.artio._artio_caller import \
-    artio_is_valid, \
-    artio_fileset, \
-    ARTIOSFCRangeHandler
-from yt.frontends.artio import _artio_caller
-from yt.frontends.artio.fields import \
-    ARTIOFieldInfo
-
-from yt.funcs import \
-    mylog, \
-    setdefaultattr
-from yt.geometry.geometry_handler import \
-    Index, \
-    YTDataChunk
+import numpy as np
+
 import yt.geometry.particle_deposit as particle_deposit
-from yt.data_objects.static_output import \
-    Dataset
-from yt.data_objects.octree_subset import \
-    OctreeSubset
-from yt.data_objects.field_data import \
-    YTFieldData
-from yt.utilities.exceptions import \
-    YTParticleDepositionNotImplemented
-from yt.data_objects.particle_unions import \
-    ParticleUnion
+from yt.data_objects.field_data import YTFieldData
+from yt.data_objects.octree_subset import OctreeSubset
+from yt.data_objects.particle_unions import ParticleUnion
+from yt.data_objects.static_output import Dataset
+from yt.frontends.artio import _artio_caller
+from yt.frontends.artio._artio_caller import (
+    ARTIOSFCRangeHandler,
+    artio_fileset,
+    artio_is_valid,
+)
+from yt.frontends.artio.fields import ARTIOFieldInfo
+from yt.funcs import mylog, setdefaultattr
+from yt.geometry.geometry_handler import Index, YTDataChunk
+from yt.utilities.exceptions import YTParticleDepositionNotImplemented
+
 
 class ARTIOOctreeSubset(OctreeSubset):
     _domain_offset = 0
diff --git a/yt/frontends/artio/fields.py b/yt/frontends/artio/fields.py
index 2dff4d492ba..d9ec3eaa27c 100644
--- a/yt/frontends/artio/fields.py
+++ b/yt/frontends/artio/fields.py
@@ -1,12 +1,9 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
-from yt.units.yt_array import \
-    YTArray
-from yt.utilities.physical_constants import \
-    boltzmann_constant_cgs, \
-    amu_cgs
 import numpy as np
 
+from yt.fields.field_info_container import FieldInfoContainer
+from yt.units.yt_array import YTArray
+from yt.utilities.physical_constants import amu_cgs, boltzmann_constant_cgs
+
 b_units = "code_magnetic"
 ra_units = "code_length / code_time**2"
 rho_units = "code_mass / code_length**3"
diff --git a/yt/frontends/artio/io.py b/yt/frontends/artio/io.py
index 95cc6f9fead..6202ec963d4 100644
--- a/yt/frontends/artio/io.py
+++ b/yt/frontends/artio/io.py
@@ -1,7 +1,6 @@
 import numpy as np
 
-from yt.utilities.io_handler import \
-    BaseIOHandler
+from yt.utilities.io_handler import BaseIOHandler
 
 
 class IOHandlerARTIO(BaseIOHandler):
diff --git a/yt/frontends/artio/tests/test_outputs.py b/yt/frontends/artio/tests/test_outputs.py
index 12a68c141bb..c9eb1b21c0f 100644
--- a/yt/frontends/artio/tests/test_outputs.py
+++ b/yt/frontends/artio/tests/test_outputs.py
@@ -1,16 +1,18 @@
 from yt.convenience import load
-from yt.testing import \
-    assert_equal, \
-    assert_allclose_units, \
-    requires_file, \
-    units_override_check
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load, \
-    PixelizedProjectionValuesTest, \
-    FieldValuesTest, \
-    create_obj
 from yt.frontends.artio.api import ARTIODataset
+from yt.testing import (
+    assert_allclose_units,
+    assert_equal,
+    requires_file,
+    units_override_check,
+)
+from yt.utilities.answer_testing.framework import (
+    FieldValuesTest,
+    PixelizedProjectionValuesTest,
+    create_obj,
+    data_dir_load,
+    requires_ds,
+)
 
 _fields = ("temperature", "density", "velocity_magnitude",
            ("deposit", "all_density"), ("deposit", "all_count"))
diff --git a/yt/frontends/athena/api.py b/yt/frontends/athena/api.py
index d6809d21dd2..f04bcab66a3 100644
--- a/yt/frontends/athena/api.py
+++ b/yt/frontends/athena/api.py
@@ -1,12 +1,4 @@
-from .data_structures import \
-      AthenaGrid, \
-      AthenaHierarchy, \
-      AthenaDataset
-
-from .fields import \
-      AthenaFieldInfo
-
-from .io import \
-      IOHandlerAthena
-
 from . import tests
+from .data_structures import AthenaDataset, AthenaGrid, AthenaHierarchy
+from .fields import AthenaFieldInfo
+from .io import IOHandlerAthena
diff --git a/yt/frontends/athena/data_structures.py b/yt/frontends/athena/data_structures.py
index e1ac69646e7..105c95cad05 100644
--- a/yt/frontends/athena/data_structures.py
+++ b/yt/frontends/athena/data_structures.py
@@ -1,27 +1,19 @@
-import numpy as np
 import os
 import weakref
 
-from yt.funcs import \
-    mylog, \
-    ensure_tuple, \
-    sglob
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.data_objects.static_output import \
-    Dataset
-from yt.utilities.chemical_formulas import \
-    default_mu
-from yt.utilities.lib.misc_utilities import \
-    get_box_grids_level
-from yt.geometry.geometry_handler import \
-    YTDataChunk
+import numpy as np
+
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset
+from yt.funcs import ensure_tuple, mylog, sglob
+from yt.geometry.geometry_handler import YTDataChunk
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.utilities.chemical_formulas import default_mu
+from yt.utilities.decompose import decompose_array, get_psize
+from yt.utilities.lib.misc_utilities import get_box_grids_level
 
 from .fields import AthenaFieldInfo
-from yt.utilities.decompose import \
-    decompose_array, get_psize
+
 
 def chk23(strin):
     return strin.encode('utf-8')
diff --git a/yt/frontends/athena/definitions.py b/yt/frontends/athena/definitions.py
index 307b63a9616..70a2797752a 100644
--- a/yt/frontends/athena/definitions.py
+++ b/yt/frontends/athena/definitions.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/athena/fields.py b/yt/frontends/athena/fields.py
index a35c7b3d1a9..11c8efb440b 100644
--- a/yt/frontends/athena/fields.py
+++ b/yt/frontends/athena/fields.py
@@ -1,7 +1,5 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
-from yt.utilities.physical_constants import \
-    kboltz, mh
+from yt.fields.field_info_container import FieldInfoContainer
+from yt.utilities.physical_constants import kboltz, mh
 
 b_units = "code_magnetic"
 pres_units = "code_pressure"
diff --git a/yt/frontends/athena/io.py b/yt/frontends/athena/io.py
index 6a510bf6839..90c2668c1a9 100644
--- a/yt/frontends/athena/io.py
+++ b/yt/frontends/athena/io.py
@@ -1,7 +1,8 @@
-from yt.utilities.io_handler import \
-    BaseIOHandler
 import numpy as np
+
 from yt.funcs import mylog
+from yt.utilities.io_handler import BaseIOHandler
+
 from .data_structures import chk23
 
 float_size = {"float":np.dtype(">f4").itemsize,
@@ -108,5 +109,3 @@ def get_read_table_offset(f):
             break
         line = f.readline()
     return read_table_offset
-
-
diff --git a/yt/frontends/athena/tests/test_outputs.py b/yt/frontends/athena/tests/test_outputs.py
index eda890eab86..b4379f8543e 100644
--- a/yt/frontends/athena/tests/test_outputs.py
+++ b/yt/frontends/athena/tests/test_outputs.py
@@ -1,16 +1,17 @@
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    assert_allclose_units, \
-    disable_dataset_cache
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    small_patch_amr, \
-    data_dir_load
-from yt.frontends.athena.api import AthenaDataset
-from yt.convenience import load
-
 import yt.units as u
+from yt.convenience import load
+from yt.frontends.athena.api import AthenaDataset
+from yt.testing import (
+    assert_allclose_units,
+    assert_equal,
+    disable_dataset_cache,
+    requires_file,
+)
+from yt.utilities.answer_testing.framework import (
+    data_dir_load,
+    requires_ds,
+    small_patch_amr,
+)
 
 _fields_cloud = ("scalar[0]", "density", "total_energy")
 
diff --git a/yt/frontends/athena_pp/api.py b/yt/frontends/athena_pp/api.py
index 497dd4e2984..40b252b71a5 100644
--- a/yt/frontends/athena_pp/api.py
+++ b/yt/frontends/athena_pp/api.py
@@ -1,12 +1,4 @@
-from .data_structures import \
-      AthenaPPGrid, \
-      AthenaPPHierarchy, \
-      AthenaPPDataset
-
-from .fields import \
-      AthenaPPFieldInfo
-
-from .io import \
-      IOHandlerAthenaPP
-
 from . import tests
+from .data_structures import AthenaPPDataset, AthenaPPGrid, AthenaPPHierarchy
+from .fields import AthenaPPFieldInfo
+from .io import IOHandlerAthenaPP
diff --git a/yt/frontends/athena_pp/data_structures.py b/yt/frontends/athena_pp/data_structures.py
index 03501b729ac..ca56f9c2dd1 100644
--- a/yt/frontends/athena_pp/data_structures.py
+++ b/yt/frontends/athena_pp/data_structures.py
@@ -1,28 +1,20 @@
-import numpy as np
 import os
 import weakref
-
-from yt.funcs import \
-    mylog, get_pbar, \
-    ensure_tuple
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.data_objects.static_output import \
-    Dataset
-from yt.geometry.geometry_handler import \
-    YTDataChunk
-from yt.utilities.file_handler import \
-    HDF5FileHandler
-from yt.geometry.unstructured_mesh_handler import \
-    UnstructuredIndex
-from yt.data_objects.unstructured_mesh import \
-    SemiStructuredMesh
 from itertools import chain, product
+
+import numpy as np
+
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset
+from yt.data_objects.unstructured_mesh import SemiStructuredMesh
+from yt.funcs import ensure_tuple, get_pbar, mylog
+from yt.geometry.geometry_handler import YTDataChunk
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.geometry.unstructured_mesh_handler import UnstructuredIndex
+from yt.utilities.chemical_formulas import default_mu
+from yt.utilities.file_handler import HDF5FileHandler
+
 from .fields import AthenaPPFieldInfo
-from yt.utilities.chemical_formulas import \
-    default_mu
 
 geom_map = {"cartesian": "cartesian",
             "cylindrical": "cylindrical",
diff --git a/yt/frontends/athena_pp/definitions.py b/yt/frontends/athena_pp/definitions.py
index 307b63a9616..70a2797752a 100644
--- a/yt/frontends/athena_pp/definitions.py
+++ b/yt/frontends/athena_pp/definitions.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/athena_pp/fields.py b/yt/frontends/athena_pp/fields.py
index 3d4003b676d..ff18f5641ed 100644
--- a/yt/frontends/athena_pp/fields.py
+++ b/yt/frontends/athena_pp/fields.py
@@ -1,7 +1,5 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
-from yt.utilities.physical_constants import \
-    kboltz, mh
+from yt.fields.field_info_container import FieldInfoContainer
+from yt.utilities.physical_constants import kboltz, mh
 
 b_units = "code_magnetic"
 pres_units = "code_mass/(code_length*code_time**2)"
diff --git a/yt/frontends/athena_pp/io.py b/yt/frontends/athena_pp/io.py
index 88763e26421..fd06d427bd9 100644
--- a/yt/frontends/athena_pp/io.py
+++ b/yt/frontends/athena_pp/io.py
@@ -1,10 +1,11 @@
-import numpy as np
 from itertools import groupby
 
-from yt.utilities.io_handler import \
-    BaseIOHandler
+import numpy as np
+
+from yt.utilities.io_handler import BaseIOHandler
 from yt.utilities.logger import ytLogger as mylog
 
+
 # http://stackoverflow.com/questions/2361945/detecting-consecutive-integers-in-a-list
 def grid_sequences(grids):
     g_iter = sorted(grids, key = lambda g: g.id)
@@ -82,4 +83,4 @@ def _read_chunk_data(self, chunk, fields):
                 data = ds[fdi,start:end,:,:,:].transpose()
                 for i, g in enumerate(gs):
                     rv[g.id][field] = np.asarray(data[...,i], "=f8")
-        return rv
\ No newline at end of file
+        return rv
diff --git a/yt/frontends/athena_pp/tests/test_outputs.py b/yt/frontends/athena_pp/tests/test_outputs.py
index d176cedde67..c83214fc554 100644
--- a/yt/frontends/athena_pp/tests/test_outputs.py
+++ b/yt/frontends/athena_pp/tests/test_outputs.py
@@ -1,16 +1,19 @@
 import numpy as np
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    units_override_check, \
-    assert_allclose
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    small_patch_amr, \
-    data_dir_load, \
-    GenericArrayTest
-from yt.frontends.athena_pp.api import AthenaPPDataset
+
 from yt.convenience import load
+from yt.frontends.athena_pp.api import AthenaPPDataset
+from yt.testing import (
+    assert_allclose,
+    assert_equal,
+    requires_file,
+    units_override_check,
+)
+from yt.utilities.answer_testing.framework import (
+    GenericArrayTest,
+    data_dir_load,
+    requires_ds,
+    small_patch_amr,
+)
 
 _fields_disk = ("density", "velocity_r")
 
diff --git a/yt/frontends/boxlib/__init__.py b/yt/frontends/boxlib/__init__.py
index 07fa1336903..a38372cd19a 100644
--- a/yt/frontends/boxlib/__init__.py
+++ b/yt/frontends/boxlib/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/boxlib/api.py b/yt/frontends/boxlib/api.py
index 0ccf409e52c..b1bfd3c0aa8 100644
--- a/yt/frontends/boxlib/api.py
+++ b/yt/frontends/boxlib/api.py
@@ -1,24 +1,22 @@
-from .data_structures import \
-      BoxlibGrid, \
-      BoxlibHierarchy, \
-      BoxlibDataset, \
-      OrionHierarchy, \
-      OrionDataset, \
-      CastroDataset, \
-      MaestroDataset, \
-      NyxDataset, \
-      NyxHierarchy, \
-      WarpXDataset, \
-      WarpXHierarchy
-
-from .fields import \
-      BoxlibFieldInfo, \
-      MaestroFieldInfo, \
-      CastroFieldInfo, \
-      NyxFieldInfo, \
-      WarpXFieldInfo
-
-from .io import \
-      IOHandlerBoxlib
-
 from . import tests
+from .data_structures import (
+    BoxlibDataset,
+    BoxlibGrid,
+    BoxlibHierarchy,
+    CastroDataset,
+    MaestroDataset,
+    NyxDataset,
+    NyxHierarchy,
+    OrionDataset,
+    OrionHierarchy,
+    WarpXDataset,
+    WarpXHierarchy,
+)
+from .fields import (
+    BoxlibFieldInfo,
+    CastroFieldInfo,
+    MaestroFieldInfo,
+    NyxFieldInfo,
+    WarpXFieldInfo,
+)
+from .io import IOHandlerBoxlib
diff --git a/yt/frontends/boxlib/data_structures.py b/yt/frontends/boxlib/data_structures.py
index 94b2adf3084..04ebb896338 100644
--- a/yt/frontends/boxlib/data_structures.py
+++ b/yt/frontends/boxlib/data_structures.py
@@ -1,34 +1,27 @@
+import glob
 import inspect
 import os
 import re
 from collections import namedtuple
-
 from stat import ST_CTIME
 
 import numpy as np
-import glob
 
-from yt.funcs import \
-    ensure_tuple, \
-    mylog, \
-    setdefaultattr
 from yt.data_objects.grid_patch import AMRGridPatch
-from yt.geometry.grid_geometry_handler import GridIndex
 from yt.data_objects.static_output import Dataset
-
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_root_only
-from yt.utilities.lib.misc_utilities import \
-    get_box_grids_level
-from yt.utilities.io_handler import \
-    io_registry
-
-from .fields import \
-    BoxlibFieldInfo, \
-    NyxFieldInfo, \
-    MaestroFieldInfo, \
-    CastroFieldInfo, \
-    WarpXFieldInfo
+from yt.funcs import ensure_tuple, mylog, setdefaultattr
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.utilities.io_handler import io_registry
+from yt.utilities.lib.misc_utilities import get_box_grids_level
+from yt.utilities.parallel_tools.parallel_analysis_interface import parallel_root_only
+
+from .fields import (
+    BoxlibFieldInfo,
+    CastroFieldInfo,
+    MaestroFieldInfo,
+    NyxFieldInfo,
+    WarpXFieldInfo,
+)
 
 # This is what we use to find scientific notation that might include d's
 # instead of e's.
diff --git a/yt/frontends/boxlib/definitions.py b/yt/frontends/boxlib/definitions.py
index aaceef492f9..f15247eef62 100644
--- a/yt/frontends/boxlib/definitions.py
+++ b/yt/frontends/boxlib/definitions.py
@@ -44,4 +44,3 @@
                   "comoving_OmM": "CosmologyOmegaMatterNow",
                   "comoving_h": "CosmologyHubbleConstantNow"
                   }
-
diff --git a/yt/frontends/boxlib/fields.py b/yt/frontends/boxlib/fields.py
index 9ad5446708f..46027eb2d81 100644
--- a/yt/frontends/boxlib/fields.py
+++ b/yt/frontends/boxlib/fields.py
@@ -1,13 +1,11 @@
-import string
 import re
+import string
+
 import numpy as np
 
-from yt.utilities.physical_constants import \
-    boltzmann_constant_cgs, amu_cgs, c
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 from yt.units import YTQuantity
-
+from yt.utilities.physical_constants import amu_cgs, boltzmann_constant_cgs, c
 
 rho_units = "code_mass / code_length**3"
 mom_units = "code_mass / (code_time * code_length**2)"
diff --git a/yt/frontends/boxlib/io.py b/yt/frontends/boxlib/io.py
index d733bb259d1..9046ef16311 100644
--- a/yt/frontends/boxlib/io.py
+++ b/yt/frontends/boxlib/io.py
@@ -1,12 +1,13 @@
 import os
-import numpy as np
 from collections import defaultdict
 
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.funcs import mylog
+import numpy as np
+
 from yt.frontends.chombo.io import parse_orion_sinks
+from yt.funcs import mylog
 from yt.geometry.selection_routines import GridSelector
+from yt.utilities.io_handler import BaseIOHandler
+
 
 def _remove_raw(all_fields, raw_fields):
     centered_fields = set(all_fields)
diff --git a/yt/frontends/boxlib/tests/test_outputs.py b/yt/frontends/boxlib/tests/test_outputs.py
index d1fdcef1cff..48fcd1a8b14 100644
--- a/yt/frontends/boxlib/tests/test_outputs.py
+++ b/yt/frontends/boxlib/tests/test_outputs.py
@@ -1,19 +1,19 @@
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    units_override_check
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    small_patch_amr, \
-    data_dir_load, \
-    GridValuesTest
-from yt.frontends.boxlib.api import \
-    OrionDataset, \
-    NyxDataset, \
-    WarpXDataset, \
-    CastroDataset, \
-    MaestroDataset
-import numpy as np    
+import numpy as np
+
+from yt.frontends.boxlib.api import (
+    CastroDataset,
+    MaestroDataset,
+    NyxDataset,
+    OrionDataset,
+    WarpXDataset,
+)
+from yt.testing import assert_equal, requires_file, units_override_check
+from yt.utilities.answer_testing.framework import (
+    GridValuesTest,
+    data_dir_load,
+    requires_ds,
+    small_patch_amr,
+)
 
 # We don't do anything needing ghost zone generation right now, because these
 # are non-periodic datasets.
diff --git a/yt/frontends/chombo/api.py b/yt/frontends/chombo/api.py
index 0edc141c133..4c4c514d630 100644
--- a/yt/frontends/chombo/api.py
+++ b/yt/frontends/chombo/api.py
@@ -1,23 +1,21 @@
-from .data_structures import \
-    ChomboGrid, \
-    ChomboHierarchy, \
-    ChomboDataset, \
-    Orion2Hierarchy, \
-    Orion2Dataset, \
-    ChomboPICHierarchy, \
-    ChomboPICDataset, \
-    PlutoHierarchy, \
-    PlutoDataset
-
-from .fields import \
-    ChomboFieldInfo, \
-    Orion2FieldInfo, \
-    ChomboPICFieldInfo1D, \
-    ChomboPICFieldInfo2D, \
-    ChomboPICFieldInfo3D, \
-    PlutoFieldInfo
-
-from .io import \
-    IOHandlerChomboHDF5
-
 from . import tests
+from .data_structures import (
+    ChomboDataset,
+    ChomboGrid,
+    ChomboHierarchy,
+    ChomboPICDataset,
+    ChomboPICHierarchy,
+    Orion2Dataset,
+    Orion2Hierarchy,
+    PlutoDataset,
+    PlutoHierarchy,
+)
+from .fields import (
+    ChomboFieldInfo,
+    ChomboPICFieldInfo1D,
+    ChomboPICFieldInfo2D,
+    ChomboPICFieldInfo3D,
+    Orion2FieldInfo,
+    PlutoFieldInfo,
+)
+from .io import IOHandlerChomboHDF5
diff --git a/yt/frontends/chombo/data_structures.py b/yt/frontends/chombo/data_structures.py
index d7b890f538e..0d5d6e151df 100644
--- a/yt/frontends/chombo/data_structures.py
+++ b/yt/frontends/chombo/data_structures.py
@@ -1,29 +1,26 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
-import re
 import os
+import re
 import weakref
+
 import numpy as np
 
-from yt.funcs import \
-    mylog, \
-    setdefaultattr
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.data_objects.static_output import \
-    Dataset
-from yt.utilities.file_handler import \
-    HDF5FileHandler, \
-    warn_h5py
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_root_only
-from yt.utilities.lib.misc_utilities import \
-    get_box_grids_level
-
-from .fields import ChomboFieldInfo, Orion2FieldInfo, \
-    ChomboPICFieldInfo1D, ChomboPICFieldInfo2D, ChomboPICFieldInfo3D, \
-    PlutoFieldInfo
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset
+from yt.funcs import mylog, setdefaultattr
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.utilities.file_handler import HDF5FileHandler, warn_h5py
+from yt.utilities.lib.misc_utilities import get_box_grids_level
+from yt.utilities.on_demand_imports import _h5py as h5py
+from yt.utilities.parallel_tools.parallel_analysis_interface import parallel_root_only
+
+from .fields import (
+    ChomboFieldInfo,
+    ChomboPICFieldInfo1D,
+    ChomboPICFieldInfo2D,
+    ChomboPICFieldInfo3D,
+    Orion2FieldInfo,
+    PlutoFieldInfo,
+)
 
 
 def is_chombo_hdf5(fn):
diff --git a/yt/frontends/chombo/definitions.py b/yt/frontends/chombo/definitions.py
index 8b137891791..e69de29bb2d 100644
--- a/yt/frontends/chombo/definitions.py
+++ b/yt/frontends/chombo/definitions.py
@@ -1 +0,0 @@
-
diff --git a/yt/frontends/chombo/fields.py b/yt/frontends/chombo/fields.py
index fadf3b72e96..e961803cd5f 100644
--- a/yt/frontends/chombo/fields.py
+++ b/yt/frontends/chombo/fields.py
@@ -1,11 +1,12 @@
 import numpy as np
-from yt.units.unit_object import Unit
-from yt.fields.field_info_container import \
-    FieldInfoContainer, \
-    particle_deposition_functions, \
-    particle_vector_functions, \
-    standard_particle_fields
 
+from yt.fields.field_info_container import (
+    FieldInfoContainer,
+    particle_deposition_functions,
+    particle_vector_functions,
+    standard_particle_fields,
+)
+from yt.units.unit_object import Unit
 from yt.utilities.exceptions import YTFieldNotFound
 
 rho_units = "code_mass / code_length**3"
diff --git a/yt/frontends/chombo/io.py b/yt/frontends/chombo/io.py
index f4625f14c8c..244109264fc 100644
--- a/yt/frontends/chombo/io.py
+++ b/yt/frontends/chombo/io.py
@@ -1,11 +1,10 @@
 import re
+
 import numpy as np
-from yt.geometry.selection_routines import \
-    GridSelector
-from yt.utilities.logger import \
-    ytLogger as mylog
-from yt.utilities.io_handler import \
-    BaseIOHandler
+
+from yt.geometry.selection_routines import GridSelector
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.logger import ytLogger as mylog
 
 
 class IOHandlerChomboHDF5(BaseIOHandler):
diff --git a/yt/frontends/chombo/tests/test_outputs.py b/yt/frontends/chombo/tests/test_outputs.py
index da8e4353b85..6d292de178b 100644
--- a/yt/frontends/chombo/tests/test_outputs.py
+++ b/yt/frontends/chombo/tests/test_outputs.py
@@ -1,15 +1,10 @@
-from yt.testing import \
-    requires_file, \
-    assert_equal, \
-    units_override_check
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    small_patch_amr, \
-    data_dir_load
-from yt.frontends.chombo.api import \
-    ChomboDataset, \
-    Orion2Dataset, \
-    PlutoDataset
+from yt.frontends.chombo.api import ChomboDataset, Orion2Dataset, PlutoDataset
+from yt.testing import assert_equal, requires_file, units_override_check
+from yt.utilities.answer_testing.framework import (
+    data_dir_load,
+    requires_ds,
+    small_patch_amr,
+)
 
 _fields = ("density", "velocity_magnitude",  # "velocity_divergence",
            "magnetic_field_x")
diff --git a/yt/frontends/eagle/api.py b/yt/frontends/eagle/api.py
index e9ee31bb242..8490cc27028 100644
--- a/yt/frontends/eagle/api.py
+++ b/yt/frontends/eagle/api.py
@@ -1,11 +1,4 @@
-from .data_structures import \
-    EagleDataset, \
-    EagleNetworkDataset
-
-from .fields import \
-    EagleNetworkFieldInfo
-
-from .io import \
-    IOHandlerEagleNetwork
-
 from . import tests
+from .data_structures import EagleDataset, EagleNetworkDataset
+from .fields import EagleNetworkFieldInfo
+from .io import IOHandlerEagleNetwork
diff --git a/yt/frontends/eagle/data_structures.py b/yt/frontends/eagle/data_structures.py
index 2577bdd636f..e3848196629 100644
--- a/yt/frontends/eagle/data_structures.py
+++ b/yt/frontends/eagle/data_structures.py
@@ -1,14 +1,12 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
 import numpy as np
 
-from yt.frontends.gadget.data_structures import \
-    GadgetHDF5Dataset
-from yt.frontends.owls.fields import \
-    OWLSFieldInfo
 import yt.units
+from yt.frontends.gadget.data_structures import GadgetHDF5Dataset
+from yt.frontends.owls.fields import OWLSFieldInfo
+from yt.utilities.on_demand_imports import _h5py as h5py
+
+from .fields import EagleNetworkFieldInfo
 
-from .fields import \
-    EagleNetworkFieldInfo
 
 class EagleDataset(GadgetHDF5Dataset):
     _particle_mass_name = "Mass"
diff --git a/yt/frontends/eagle/fields.py b/yt/frontends/eagle/fields.py
index 0b11a4fad5d..c55964bffbe 100644
--- a/yt/frontends/eagle/fields.py
+++ b/yt/frontends/eagle/fields.py
@@ -1,10 +1,8 @@
-from yt.frontends.owls.fields import \
-    OWLSFieldInfo
+from yt.frontends.eagle.definitions import eaglenetwork_ion_lookup
+from yt.frontends.owls.fields import OWLSFieldInfo
 from yt.units.yt_array import YTQuantity
 from yt.utilities.periodic_table import periodic_table
 
-from yt.frontends.eagle.definitions import \
-    eaglenetwork_ion_lookup
 
 class EagleNetworkFieldInfo(OWLSFieldInfo):
 
diff --git a/yt/frontends/eagle/io.py b/yt/frontends/eagle/io.py
index 1ed10ddcb63..757692bec30 100644
--- a/yt/frontends/eagle/io.py
+++ b/yt/frontends/eagle/io.py
@@ -1,5 +1,5 @@
-from yt.frontends.owls.io import \
-    IOHandlerOWLS
+from yt.frontends.owls.io import IOHandlerOWLS
+
 
 class IOHandlerEagleNetwork(IOHandlerOWLS):
     _dataset_type = "eagle_network"
diff --git a/yt/frontends/eagle/tests/test_outputs.py b/yt/frontends/eagle/tests/test_outputs.py
index bdf1992cb15..f80aa0264a4 100644
--- a/yt/frontends/eagle/tests/test_outputs.py
+++ b/yt/frontends/eagle/tests/test_outputs.py
@@ -1,9 +1,6 @@
-from yt.testing import \
-    requires_file, \
-    ParticleSelectionComparison
-from yt.utilities.answer_testing.framework import \
-    data_dir_load
 from yt.frontends.eagle.api import EagleDataset
+from yt.testing import ParticleSelectionComparison, requires_file
+from yt.utilities.answer_testing.framework import data_dir_load
 
 s28 = "snapshot_028_z000p000/snap_028_z000p000.0.hdf5"
 @requires_file(s28)
diff --git a/yt/frontends/enzo/answer_testing_support.py b/yt/frontends/enzo/answer_testing_support.py
index 9dbc844f027..4f594bcc6aa 100644
--- a/yt/frontends/enzo/answer_testing_support.py
+++ b/yt/frontends/enzo/answer_testing_support.py
@@ -1,18 +1,19 @@
-import numpy as np
 import os
-
 from functools import wraps
 
+import numpy as np
+
 from yt.config import ytcfg
 from yt.convenience import load
 from yt.testing import assert_allclose
-from yt.utilities.answer_testing.framework import \
-    AnswerTestingTest, \
-    can_run_ds, \
-    FieldValuesTest, \
-    GridValuesTest, \
-    ProjectionValuesTest, \
-    temp_cwd
+from yt.utilities.answer_testing.framework import (
+    AnswerTestingTest,
+    FieldValuesTest,
+    GridValuesTest,
+    ProjectionValuesTest,
+    can_run_ds,
+    temp_cwd,
+)
 
 
 class AssertWrapper:
diff --git a/yt/frontends/enzo/api.py b/yt/frontends/enzo/api.py
index b1349d43faa..ab24e3d54a8 100644
--- a/yt/frontends/enzo/api.py
+++ b/yt/frontends/enzo/api.py
@@ -1,24 +1,21 @@
-from .data_structures import \
-      EnzoGrid, \
-      EnzoGridInMemory, \
-      EnzoHierarchy, \
-      EnzoHierarchyInMemory, \
-      EnzoHierarchy1D, \
-      EnzoHierarchy2D, \
-      EnzoDataset, \
-      EnzoDatasetInMemory
-
-from .simulation_handling import \
-    EnzoSimulation
+from . import tests
+from .data_structures import (
+    EnzoDataset,
+    EnzoDatasetInMemory,
+    EnzoGrid,
+    EnzoGridInMemory,
+    EnzoHierarchy,
+    EnzoHierarchy1D,
+    EnzoHierarchy2D,
+    EnzoHierarchyInMemory,
+)
+from .fields import EnzoFieldInfo
+from .io import (
+    IOHandlerInMemory,
+    IOHandlerPacked1D,
+    IOHandlerPacked2D,
+    IOHandlerPackedHDF5,
+)
+from .simulation_handling import EnzoSimulation
 
-from .fields import \
-      EnzoFieldInfo
 add_enzo_field = EnzoFieldInfo.add_field
-
-from .io import \
-      IOHandlerPackedHDF5, \
-      IOHandlerInMemory, \
-      IOHandlerPacked2D, \
-      IOHandlerPacked1D
-
-from . import tests
diff --git a/yt/frontends/enzo/data_structures.py b/yt/frontends/enzo/data_structures.py
index 505d6e0fb69..e108d5d88f1 100644
--- a/yt/frontends/enzo/data_structures.py
+++ b/yt/frontends/enzo/data_structures.py
@@ -1,37 +1,24 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
 import io
-import weakref
-import numpy as np
 import os
+import re
 import string
 import time
-import re
-
-from yt.utilities.on_demand_imports import \
-    _libconf as libconf
+import weakref
 from collections import defaultdict
 
-from yt.frontends.enzo.misc import \
-    cosmology_get_units
-from yt.funcs import \
-    ensure_list, \
-    ensure_tuple, \
-    get_pbar, \
-    setdefaultattr
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.geometry.geometry_handler import \
-    YTDataChunk
-from yt.data_objects.static_output import \
-    Dataset
-from yt.fields.field_info_container import \
-    NullFunc
+import numpy as np
+
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset
+from yt.fields.field_info_container import NullFunc
+from yt.frontends.enzo.misc import cosmology_get_units
+from yt.funcs import ensure_list, ensure_tuple, get_pbar, setdefaultattr
+from yt.geometry.geometry_handler import YTDataChunk
+from yt.geometry.grid_geometry_handler import GridIndex
 from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.on_demand_imports import _h5py as h5py, _libconf as libconf
 
-from .fields import \
-    EnzoFieldInfo
+from .fields import EnzoFieldInfo
 
 
 class EnzoGrid(AMRGridPatch):
diff --git a/yt/frontends/enzo/fields.py b/yt/frontends/enzo/fields.py
index 1fc35263864..54bb0db36f1 100644
--- a/yt/frontends/enzo/fields.py
+++ b/yt/frontends/enzo/fields.py
@@ -1,9 +1,7 @@
 import numpy as np
-from yt.fields.field_info_container import \
-    FieldInfoContainer
-from yt.utilities.physical_constants import \
-    me, \
-    mp
+
+from yt.fields.field_info_container import FieldInfoContainer
+from yt.utilities.physical_constants import me, mp
 
 b_units = "code_magnetic"
 e_units = "code_magnetic/c"
diff --git a/yt/frontends/enzo/io.py b/yt/frontends/enzo/io.py
index 04230028f6b..eae796f4178 100644
--- a/yt/frontends/enzo/io.py
+++ b/yt/frontends/enzo/io.py
@@ -1,10 +1,9 @@
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.utilities.logger import ytLogger as mylog
-from yt.utilities.on_demand_imports import _h5py as h5py
-from yt.geometry.selection_routines import GridSelector
 import numpy as np
 
+from yt.geometry.selection_routines import GridSelector
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.on_demand_imports import _h5py as h5py
 
 _convert_mass = ("particle_mass","mass")
 
diff --git a/yt/frontends/enzo/misc.py b/yt/frontends/enzo/misc.py
index 9d45fdd98f2..08f2753ef33 100644
--- a/yt/frontends/enzo/misc.py
+++ b/yt/frontends/enzo/misc.py
@@ -1,11 +1,13 @@
 import numpy as np
 
-from yt.utilities.physical_ratios import \
-    boltzmann_constant_erg_per_K, \
-    cm_per_mpc, \
-    mass_hydrogen_grams, \
-    newton_cgs, \
-    rho_crit_g_cm3_h2
+from yt.utilities.physical_ratios import (
+    boltzmann_constant_erg_per_K,
+    cm_per_mpc,
+    mass_hydrogen_grams,
+    newton_cgs,
+    rho_crit_g_cm3_h2,
+)
+
 
 def cosmology_get_units(hubble_constant, omega_matter, box_size,
                         initial_redshift, current_redshift):
diff --git a/yt/frontends/enzo/simulation_handling.py b/yt/frontends/enzo/simulation_handling.py
index 3e4f4d2c43d..f044e838767 100644
--- a/yt/frontends/enzo/simulation_handling.py
+++ b/yt/frontends/enzo/simulation_handling.py
@@ -1,30 +1,23 @@
-import numpy as np
 import glob
 import os
 
-from unyt import \
-    dimensions, \
-    unyt_array
-from unyt.unit_registry import \
-    UnitRegistry
-
-from yt.convenience import \
-    load
-from yt.funcs import \
-    only_on_root
-from yt.data_objects.time_series import \
-    SimulationTimeSeries, DatasetSeries
-from yt.utilities.cosmology import \
-    Cosmology
-from yt.utilities.exceptions import \
-    InvalidSimulationTimeSeries, \
-    MissingParameter, \
-    NoStoppingCondition, \
-    YTOutputNotIdentified
-from yt.utilities.logger import ytLogger as \
-    mylog
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_objects
+import numpy as np
+from unyt import dimensions, unyt_array
+from unyt.unit_registry import UnitRegistry
+
+from yt.convenience import load
+from yt.data_objects.time_series import DatasetSeries, SimulationTimeSeries
+from yt.funcs import only_on_root
+from yt.utilities.cosmology import Cosmology
+from yt.utilities.exceptions import (
+    InvalidSimulationTimeSeries,
+    MissingParameter,
+    NoStoppingCondition,
+    YTOutputNotIdentified,
+)
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.parallel_tools.parallel_analysis_interface import parallel_objects
+
 
 class EnzoSimulation(SimulationTimeSeries):
     r"""
diff --git a/yt/frontends/enzo/tests/test_outputs.py b/yt/frontends/enzo/tests/test_outputs.py
index affe08d2b8a..f9653492593 100644
--- a/yt/frontends/enzo/tests/test_outputs.py
+++ b/yt/frontends/enzo/tests/test_outputs.py
@@ -1,21 +1,22 @@
 import numpy as np
 
-from yt.testing import \
-    assert_almost_equal, \
-    assert_equal, \
-    requires_file, \
-    units_override_check, \
-    assert_array_equal, \
-    assert_allclose_units
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    small_patch_amr, \
-    big_patch_amr, \
-    data_dir_load
-from yt.visualization.plot_window import \
-    SlicePlot
 from yt.frontends.enzo.api import EnzoDataset
 from yt.frontends.enzo.fields import NODAL_FLAGS
+from yt.testing import (
+    assert_allclose_units,
+    assert_almost_equal,
+    assert_array_equal,
+    assert_equal,
+    requires_file,
+    units_override_check,
+)
+from yt.utilities.answer_testing.framework import (
+    big_patch_amr,
+    data_dir_load,
+    requires_ds,
+    small_patch_amr,
+)
+from yt.visualization.plot_window import SlicePlot
 
 _fields = ("temperature", "density", "velocity_magnitude",
            "velocity_divergence")
diff --git a/yt/frontends/enzo_p/api.py b/yt/frontends/enzo_p/api.py
index 76010d668d2..a5fdbfc873c 100644
--- a/yt/frontends/enzo_p/api.py
+++ b/yt/frontends/enzo_p/api.py
@@ -1,13 +1,6 @@
-from .data_structures import \
-    EnzoPGrid, \
-    EnzoPHierarchy, \
-    EnzoPDataset
+from . import tests
+from .data_structures import EnzoPDataset, EnzoPGrid, EnzoPHierarchy
+from .fields import EnzoPFieldInfo
+from .io import EnzoPIOHandler
 
-from .fields import \
-    EnzoPFieldInfo
 add_enzop_field = EnzoPFieldInfo.add_field
-
-from .io import \
-     EnzoPIOHandler
-
-from . import tests
diff --git a/yt/frontends/enzo_p/data_structures.py b/yt/frontends/enzo_p/data_structures.py
index 53c30ca4e87..fe42d284d4f 100644
--- a/yt/frontends/enzo_p/data_structures.py
+++ b/yt/frontends/enzo_p/data_structures.py
@@ -1,40 +1,28 @@
-from yt.utilities.on_demand_imports import \
-    _h5py as h5py
-from yt.utilities.on_demand_imports import \
-    _libconf as libconf
 import io as io
-import numpy as np
 import os
 import warnings
 
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.data_objects.static_output import \
-    Dataset
-from yt.fields.field_info_container import \
-    NullFunc
-from yt.frontends.enzo.misc import \
-    cosmology_get_units
-from yt.funcs import \
-    ensure_tuple, \
-    get_pbar, \
-    setdefaultattr
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.utilities.cosmology import \
-    Cosmology
-from yt.utilities.logger import \
-    ytLogger as mylog
-
-from yt.frontends.enzo_p.fields import \
-    EnzoPFieldInfo
-from yt.frontends.enzo_p.misc import \
-    get_block_info, \
-    get_child_index, \
-    get_root_blocks, \
-    get_root_block_id, \
-    nested_dict_get, \
-    is_parent
+import numpy as np
+
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset
+from yt.fields.field_info_container import NullFunc
+from yt.frontends.enzo.misc import cosmology_get_units
+from yt.frontends.enzo_p.fields import EnzoPFieldInfo
+from yt.frontends.enzo_p.misc import (
+    get_block_info,
+    get_child_index,
+    get_root_block_id,
+    get_root_blocks,
+    is_parent,
+    nested_dict_get,
+)
+from yt.funcs import ensure_tuple, get_pbar, setdefaultattr
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.utilities.cosmology import Cosmology
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.on_demand_imports import _h5py as h5py, _libconf as libconf
+
 
 class EnzoPGrid(AMRGridPatch):
     """
diff --git a/yt/frontends/enzo_p/fields.py b/yt/frontends/enzo_p/fields.py
index 4b60830058a..57b18fceada 100644
--- a/yt/frontends/enzo_p/fields.py
+++ b/yt/frontends/enzo_p/fields.py
@@ -1,9 +1,6 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
-from yt.fields.particle_fields import \
-    add_union_field
-from yt.frontends.enzo_p.misc import \
-    nested_dict_get
+from yt.fields.field_info_container import FieldInfoContainer
+from yt.fields.particle_fields import add_union_field
+from yt.frontends.enzo_p.misc import nested_dict_get
 
 rho_units = "code_mass / code_length**3"
 vel_units = "code_velocity"
diff --git a/yt/frontends/enzo_p/io.py b/yt/frontends/enzo_p/io.py
index ec190190bb2..def63ff22c5 100644
--- a/yt/frontends/enzo_p/io.py
+++ b/yt/frontends/enzo_p/io.py
@@ -1,10 +1,9 @@
-from yt.utilities.exceptions import \
-    YTException
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.utilities.on_demand_imports import _h5py as h5py
 import numpy as np
 
+from yt.utilities.exceptions import YTException
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.on_demand_imports import _h5py as h5py
+
 _particle_position_names = {}
 
 class EnzoPIOHandler(BaseIOHandler):
diff --git a/yt/frontends/enzo_p/misc.py b/yt/frontends/enzo_p/misc.py
index 3392f4520ab..c2880bd2c10 100644
--- a/yt/frontends/enzo_p/misc.py
+++ b/yt/frontends/enzo_p/misc.py
@@ -1,7 +1,7 @@
 import numpy as np
 
-from yt.funcs import \
-    ensure_tuple
+from yt.funcs import ensure_tuple
+
 
 def bdecode(block):
     """
diff --git a/yt/frontends/enzo_p/tests/test_misc.py b/yt/frontends/enzo_p/tests/test_misc.py
index da6ec704f52..b3276405dcc 100644
--- a/yt/frontends/enzo_p/tests/test_misc.py
+++ b/yt/frontends/enzo_p/tests/test_misc.py
@@ -1,11 +1,13 @@
 import numpy as np
 
-from yt.frontends.enzo_p.misc import \
-    get_block_info, \
-    get_root_blocks, \
-    get_root_block_id, \
-    is_parent, \
-    nested_dict_get
+from yt.frontends.enzo_p.misc import (
+    get_block_info,
+    get_root_block_id,
+    get_root_blocks,
+    is_parent,
+    nested_dict_get,
+)
+
 
 def get_random_block_string(max_n=64, random_state=None, level=None):
     if max_n == 1:
diff --git a/yt/frontends/enzo_p/tests/test_outputs.py b/yt/frontends/enzo_p/tests/test_outputs.py
index f9210c4fef3..370b77a0a6e 100644
--- a/yt/frontends/enzo_p/tests/test_outputs.py
+++ b/yt/frontends/enzo_p/tests/test_outputs.py
@@ -1,19 +1,15 @@
 import numpy as np
 
-from yt.utilities.on_demand_imports import \
-    _h5py as h5py
-
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    assert_array_equal
-from yt.utilities.answer_testing.framework import \
-    create_obj, \
-    data_dir_load, \
-    requires_ds, \
-    PixelizedProjectionValuesTest, \
-    FieldValuesTest
 from yt.frontends.enzo_p.api import EnzoPDataset
+from yt.testing import assert_array_equal, assert_equal, requires_file
+from yt.utilities.answer_testing.framework import (
+    FieldValuesTest,
+    PixelizedProjectionValuesTest,
+    create_obj,
+    data_dir_load,
+    requires_ds,
+)
+from yt.utilities.on_demand_imports import _h5py as h5py
 
 _fields = ("density", "total_energy",
            "velocity_x", "velocity_y")
diff --git a/yt/frontends/exodus_ii/__init__.py b/yt/frontends/exodus_ii/__init__.py
index aabf7b36d63..8e72fd8199b 100644
--- a/yt/frontends/exodus_ii/__init__.py
+++ b/yt/frontends/exodus_ii/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/exodus_ii/api.py b/yt/frontends/exodus_ii/api.py
index ae0693f14ee..fcac8ddbad0 100644
--- a/yt/frontends/exodus_ii/api.py
+++ b/yt/frontends/exodus_ii/api.py
@@ -1,15 +1,9 @@
-from .data_structures import \
-    ExodusIIUnstructuredMesh, \
-    ExodusIIUnstructuredIndex, \
-    ExodusIIDataset
-
-from .simulation_handling import \
-    ExodusIISimulation
-
-from .fields import \
-    ExodusIIFieldInfo
-
-from .io import \
-    IOHandlerExodusII
-
 from . import tests
+from .data_structures import (
+    ExodusIIDataset,
+    ExodusIIUnstructuredIndex,
+    ExodusIIUnstructuredMesh,
+)
+from .fields import ExodusIIFieldInfo
+from .io import IOHandlerExodusII
+from .simulation_handling import ExodusIISimulation
diff --git a/yt/frontends/exodus_ii/data_structures.py b/yt/frontends/exodus_ii/data_structures.py
index d7118fec595..4b2ba2b6f23 100644
--- a/yt/frontends/exodus_ii/data_structures.py
+++ b/yt/frontends/exodus_ii/data_structures.py
@@ -1,24 +1,15 @@
 import numpy as np
 
-from yt.funcs import \
-    setdefaultattr
-from yt.geometry.unstructured_mesh_handler import \
-    UnstructuredIndex
-from yt.data_objects.unstructured_mesh import \
-    UnstructuredMesh
-from yt.data_objects.static_output import \
-    Dataset
+from yt.data_objects.static_output import Dataset
 from yt.data_objects.unions import MeshUnion
-from yt.utilities.file_handler import \
-    NetCDF4FileHandler, \
-    warn_netcdf
+from yt.data_objects.unstructured_mesh import UnstructuredMesh
+from yt.funcs import setdefaultattr
+from yt.geometry.unstructured_mesh_handler import UnstructuredIndex
+from yt.utilities.file_handler import NetCDF4FileHandler, warn_netcdf
 from yt.utilities.logger import ytLogger as mylog
-from .fields import \
-    ExodusIIFieldInfo
-from .util import \
-    load_info_records, \
-    sanitize_string, \
-    get_num_pseudo_dims
+
+from .fields import ExodusIIFieldInfo
+from .util import get_num_pseudo_dims, load_info_records, sanitize_string
 
 
 class ExodusIIUnstructuredMesh(UnstructuredMesh):
diff --git a/yt/frontends/exodus_ii/fields.py b/yt/frontends/exodus_ii/fields.py
index 2797db48d06..a6a0b21e892 100644
--- a/yt/frontends/exodus_ii/fields.py
+++ b/yt/frontends/exodus_ii/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 # We need to specify which fields we might have in our dataset.  The field info
 # container subclass here will define which fields it knows about.  There are
diff --git a/yt/frontends/exodus_ii/io.py b/yt/frontends/exodus_ii/io.py
index ffda8d31aa5..d26b735570b 100644
--- a/yt/frontends/exodus_ii/io.py
+++ b/yt/frontends/exodus_ii/io.py
@@ -1,8 +1,7 @@
 import numpy as np
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.utilities.file_handler import \
-    NetCDF4FileHandler
+
+from yt.utilities.file_handler import NetCDF4FileHandler
+from yt.utilities.io_handler import BaseIOHandler
 
 
 class IOHandlerExodusII(BaseIOHandler):
diff --git a/yt/frontends/exodus_ii/simulation_handling.py b/yt/frontends/exodus_ii/simulation_handling.py
index f8668290eb8..7a292f96478 100644
--- a/yt/frontends/exodus_ii/simulation_handling.py
+++ b/yt/frontends/exodus_ii/simulation_handling.py
@@ -1,19 +1,12 @@
 import glob
 import os
-from yt.convenience import \
-    load
-from yt.funcs import \
-    only_on_root
-from yt.utilities.exceptions import \
-    YTOutputNotIdentified
-from yt.utilities.logger import ytLogger as \
-    mylog
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_objects
-from yt.data_objects.time_series import \
-    DatasetSeries, \
-    RegisteredSimulationTimeSeries
 
+from yt.convenience import load
+from yt.data_objects.time_series import DatasetSeries, RegisteredSimulationTimeSeries
+from yt.funcs import only_on_root
+from yt.utilities.exceptions import YTOutputNotIdentified
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.parallel_tools.parallel_analysis_interface import parallel_objects
 
 
 class ExodusIISimulation(DatasetSeries, metaclass = RegisteredSimulationTimeSeries):
diff --git a/yt/frontends/exodus_ii/tests/test_outputs.py b/yt/frontends/exodus_ii/tests/test_outputs.py
index 08504c217cb..21d74fbd277 100644
--- a/yt/frontends/exodus_ii/tests/test_outputs.py
+++ b/yt/frontends/exodus_ii/tests/test_outputs.py
@@ -1,12 +1,9 @@
-from yt.testing import \
-    assert_equal, \
-    assert_array_equal, \
-    requires_file
-from yt.utilities.answer_testing.framework import \
-    data_dir_load, \
-    requires_ds, \
-    GenericArrayTest
-
+from yt.testing import assert_array_equal, assert_equal, requires_file
+from yt.utilities.answer_testing.framework import (
+    GenericArrayTest,
+    data_dir_load,
+    requires_ds,
+)
 
 out = "ExodusII/out.e"
 
diff --git a/yt/frontends/exodus_ii/util.py b/yt/frontends/exodus_ii/util.py
index 07f3263b503..8880e814359 100644
--- a/yt/frontends/exodus_ii/util.py
+++ b/yt/frontends/exodus_ii/util.py
@@ -1,9 +1,10 @@
-import numpy as np
-import sys
+import re
 import string
-from itertools import takewhile
+import sys
 from collections import OrderedDict
-import re
+from itertools import takewhile
+
+import numpy as np
 
 _printable = set([ord(_) for _ in string.printable])
 
diff --git a/yt/frontends/fits/api.py b/yt/frontends/fits/api.py
index 89013272a13..e5a5f7d9662 100644
--- a/yt/frontends/fits/api.py
+++ b/yt/frontends/fits/api.py
@@ -1,19 +1,13 @@
-from .data_structures import \
-      FITSGrid, \
-      FITSHierarchy, \
-      FITSDataset, \
-      SpectralCubeFITSHierarchy, \
-      SpectralCubeFITSDataset, \
-      SkyDataFITSDataset, \
-      EventsFITSDataset
-
-from .fields import \
-      FITSFieldInfo
-
-from .io import \
-      IOHandlerFITS
-
-from .misc import \
-      setup_counts_fields
-
 from . import tests
+from .data_structures import (
+    EventsFITSDataset,
+    FITSDataset,
+    FITSGrid,
+    FITSHierarchy,
+    SkyDataFITSDataset,
+    SpectralCubeFITSDataset,
+    SpectralCubeFITSHierarchy,
+)
+from .fields import FITSFieldInfo
+from .io import IOHandlerFITS
+from .misc import setup_counts_fields
diff --git a/yt/frontends/fits/data_structures.py b/yt/frontends/fits/data_structures.py
index a2f0345343e..e879d75d33d 100644
--- a/yt/frontends/fits/data_structures.py
+++ b/yt/frontends/fits/data_structures.py
@@ -1,43 +1,29 @@
-import numpy as np
-import numpy.core.defchararray as np_char
 import os
 import time
 import uuid
-import weakref
 import warnings
-
+import weakref
 from collections import defaultdict
 
+import numpy as np
+import numpy.core.defchararray as np_char
+
 from yt.config import ytcfg
-from yt.funcs import \
-    ensure_list, \
-    mylog, \
-    setdefaultattr
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.geometry.geometry_handler import \
-    YTDataChunk
-from yt.data_objects.static_output import \
-    Dataset
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset
+from yt.funcs import ensure_list, issue_deprecation_warning, mylog, setdefaultattr
+from yt.geometry.geometry_handler import YTDataChunk
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.units import dimensions
+from yt.units.unit_lookup_table import default_unit_symbol_lut, unit_prefixes
 from yt.units.unit_object import UnitParseError
 from yt.units.yt_array import YTQuantity
-from yt.utilities.file_handler import \
-    FITSFileHandler
-from yt.utilities.io_handler import \
-    io_registry
-from .fields import FITSFieldInfo, \
-    WCSFITSFieldInfo, YTFITSFieldInfo
-from yt.utilities.decompose import \
-    decompose_array, get_psize
-from yt.funcs import issue_deprecation_warning
-from yt.units import dimensions
-from yt.units.unit_lookup_table import \
-    default_unit_symbol_lut, \
-    unit_prefixes
-from yt.utilities.on_demand_imports import \
-    _astropy, NotAModule
+from yt.utilities.decompose import decompose_array, get_psize
+from yt.utilities.file_handler import FITSFileHandler
+from yt.utilities.io_handler import io_registry
+from yt.utilities.on_demand_imports import NotAModule, _astropy
+
+from .fields import FITSFieldInfo, WCSFITSFieldInfo, YTFITSFieldInfo
 
 lon_prefixes = ["X","RA","GLON","LINEAR"]
 lat_prefixes = ["Y","DEC","GLAT","LINEAR"]
diff --git a/yt/frontends/fits/fields.py b/yt/frontends/fits/fields.py
index 4e2e0980d2c..096e681f54c 100644
--- a/yt/frontends/fits/fields.py
+++ b/yt/frontends/fits/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 
 class FITSFieldInfo(FieldInfoContainer):
diff --git a/yt/frontends/fits/io.py b/yt/frontends/fits/io.py
index d93fe1ae3f9..b0035c2951a 100644
--- a/yt/frontends/fits/io.py
+++ b/yt/frontends/fits/io.py
@@ -1,9 +1,9 @@
 import numpy as np
 
-from yt.utilities.io_handler import \
-    BaseIOHandler
+from yt.utilities.io_handler import BaseIOHandler
 from yt.utilities.logger import ytLogger as mylog
 
+
 class IOHandlerFITS(BaseIOHandler):
     _particle_reader = False
     _dataset_type = "fits"
diff --git a/yt/frontends/fits/misc.py b/yt/frontends/fits/misc.py
index c6ac7f28ef9..ee8387fcbd6 100644
--- a/yt/frontends/fits/misc.py
+++ b/yt/frontends/fits/misc.py
@@ -1,12 +1,14 @@
-import numpy as np
 import base64
+import os
+from io import BytesIO
+
+import numpy as np
+
 from yt.fields.derived_field import ValidateSpatial
-from yt.funcs import mylog, issue_deprecation_warning
+from yt.funcs import issue_deprecation_warning, mylog
+from yt.units.yt_array import YTArray, YTQuantity
 from yt.utilities.on_demand_imports import _astropy
-from yt.units.yt_array import YTQuantity, YTArray
-from io import BytesIO
 
-import os
 
 def _make_counts(emin, emax):
     def _counts(field, data):
diff --git a/yt/frontends/fits/tests/test_outputs.py b/yt/frontends/fits/tests/test_outputs.py
index 6563b0fefe5..364f75f8c97 100644
--- a/yt/frontends/fits/tests/test_outputs.py
+++ b/yt/frontends/fits/tests/test_outputs.py
@@ -1,15 +1,16 @@
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    units_override_check
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    small_patch_amr, \
-    data_dir_load
-from ..data_structures import FITSDataset, \
-    SpectralCubeFITSDataset, \
-    SkyDataFITSDataset, \
-    EventsFITSDataset
+from yt.testing import assert_equal, requires_file, units_override_check
+from yt.utilities.answer_testing.framework import (
+    data_dir_load,
+    requires_ds,
+    small_patch_amr,
+)
+
+from ..data_structures import (
+    EventsFITSDataset,
+    FITSDataset,
+    SkyDataFITSDataset,
+    SpectralCubeFITSDataset,
+)
 
 _fields_grs = ("temperature",)
 
@@ -79,4 +80,3 @@ def test_EventsFITSDataset():
 @requires_file(A2052)
 def test_SkyDataFITSDataset():
     assert isinstance(data_dir_load(A2052), SkyDataFITSDataset)
-
diff --git a/yt/frontends/flash/__init__.py b/yt/frontends/flash/__init__.py
index 40d9d41e9d6..df0a487c265 100644
--- a/yt/frontends/flash/__init__.py
+++ b/yt/frontends/flash/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/flash/api.py b/yt/frontends/flash/api.py
index dacd64a284f..39f570487cd 100644
--- a/yt/frontends/flash/api.py
+++ b/yt/frontends/flash/api.py
@@ -1,14 +1,9 @@
-from .data_structures import \
-      FLASHGrid, \
-      FLASHHierarchy, \
-      FLASHDataset, \
-      FLASHParticleDataset
-
-from .fields import \
-      FLASHFieldInfo
-
-from .io import \
-      IOHandlerFLASH, \
-      IOHandlerFLASHParticle
-
 from . import tests
+from .data_structures import (
+    FLASHDataset,
+    FLASHGrid,
+    FLASHHierarchy,
+    FLASHParticleDataset,
+)
+from .fields import FLASHFieldInfo
+from .io import IOHandlerFLASH, IOHandlerFLASHParticle
diff --git a/yt/frontends/flash/data_structures.py b/yt/frontends/flash/data_structures.py
index 24167d94f8d..4f6f3592b12 100644
--- a/yt/frontends/flash/data_structures.py
+++ b/yt/frontends/flash/data_structures.py
@@ -1,24 +1,16 @@
 import os
-import numpy as np
 import weakref
 
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.data_objects.static_output import \
-    Dataset, \
-    ParticleFile, \
-    validate_index_order
-from yt.funcs import \
-    mylog, \
-    setdefaultattr
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
-from yt.utilities.file_handler import \
-    HDF5FileHandler, \
-    warn_h5py
+import numpy as np
+
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset, ParticleFile, validate_index_order
+from yt.funcs import mylog, setdefaultattr
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.geometry.particle_geometry_handler import ParticleIndex
+from yt.utilities.file_handler import HDF5FileHandler, warn_h5py
 from yt.utilities.physical_ratios import cm_per_mpc
+
 from .fields import FLASHFieldInfo
 
 
diff --git a/yt/frontends/flash/fields.py b/yt/frontends/flash/fields.py
index 906a1c54f57..457c063d3fb 100644
--- a/yt/frontends/flash/fields.py
+++ b/yt/frontends/flash/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 # Common fields in FLASH: (Thanks to John ZuHone for this list)
 #
diff --git a/yt/frontends/flash/io.py b/yt/frontends/flash/io.py
index e74f5adae7c..06c44a11e1c 100644
--- a/yt/frontends/flash/io.py
+++ b/yt/frontends/flash/io.py
@@ -1,11 +1,11 @@
-import numpy as np
 from itertools import groupby
 
-from yt.utilities.io_handler import \
-    BaseIOHandler
+import numpy as np
+
 from yt.geometry.selection_routines import AlwaysSelector
-from yt.utilities.lib.geometry_utils import \
-    compute_morton
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.lib.geometry_utils import compute_morton
+
 
 # http://stackoverflow.com/questions/2361945/detecting-consecutive-integers-in-a-list
 def particle_sequences(grids):
diff --git a/yt/frontends/flash/tests/test_outputs.py b/yt/frontends/flash/tests/test_outputs.py
index ebd288273d9..0a62ed824fc 100644
--- a/yt/frontends/flash/tests/test_outputs.py
+++ b/yt/frontends/flash/tests/test_outputs.py
@@ -1,18 +1,21 @@
-import numpy as np
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    units_override_check, \
-    ParticleSelectionComparison
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    small_patch_amr, \
-    data_dir_load, \
-    nbody_answer
-from yt.frontends.flash.api import FLASHDataset, \
-    FLASHParticleDataset
 from collections import OrderedDict
 
+import numpy as np
+
+from yt.frontends.flash.api import FLASHDataset, FLASHParticleDataset
+from yt.testing import (
+    ParticleSelectionComparison,
+    assert_equal,
+    requires_file,
+    units_override_check,
+)
+from yt.utilities.answer_testing.framework import (
+    data_dir_load,
+    nbody_answer,
+    requires_ds,
+    small_patch_amr,
+)
+
 _fields = ("temperature", "density", "velocity_magnitude")
 
 sloshing = "GasSloshingLowRes/sloshing_low_res_hdf5_plt_cnt_0300"
diff --git a/yt/frontends/gadget/api.py b/yt/frontends/gadget/api.py
index 599324ae9ec..73e614c89a9 100644
--- a/yt/frontends/gadget/api.py
+++ b/yt/frontends/gadget/api.py
@@ -1,13 +1,4 @@
-from .data_structures import \
-    GadgetDataset, \
-    GadgetHDF5Dataset, \
-    GadgetFieldInfo
-
-from .io import \
-    IOHandlerGadgetBinary, \
-    IOHandlerGadgetHDF5
-
-from .simulation_handling import \
-    GadgetSimulation
-
 from . import tests
+from .data_structures import GadgetDataset, GadgetFieldInfo, GadgetHDF5Dataset
+from .io import IOHandlerGadgetBinary, IOHandlerGadgetHDF5
+from .simulation_handling import GadgetSimulation
diff --git a/yt/frontends/gadget/data_structures.py b/yt/frontends/gadget/data_structures.py
index 41268f2a7e5..f9cf58bdba1 100644
--- a/yt/frontends/gadget/data_structures.py
+++ b/yt/frontends/gadget/data_structures.py
@@ -1,29 +1,26 @@
-from yt.funcs import only_on_root
-from yt.utilities.on_demand_imports import _h5py as h5py
-import numpy as np
+import os
 import stat
 import struct
-import os
 
-from yt.data_objects.static_output import \
-    ParticleFile
-from yt.frontends.sph.data_structures import \
-    SPHDataset, \
-    SPHParticleIndex
+import numpy as np
+
+from yt.data_objects.static_output import ParticleFile
+from yt.frontends.sph.data_structures import SPHDataset, SPHParticleIndex
+from yt.funcs import only_on_root
 from yt.utilities.chemical_formulas import default_mu
-from yt.utilities.cosmology import \
-    Cosmology
+from yt.utilities.cosmology import Cosmology
 from yt.utilities.fortran_utils import read_record
 from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.on_demand_imports import _h5py as h5py
 
-from .definitions import \
-    gadget_header_specs, \
-    gadget_field_specs, \
-    gadget_ptype_specs, \
-    SNAP_FORMAT_2_OFFSET
+from .definitions import (
+    SNAP_FORMAT_2_OFFSET,
+    gadget_field_specs,
+    gadget_header_specs,
+    gadget_ptype_specs,
+)
+from .fields import GadgetFieldInfo
 
-from .fields import \
-    GadgetFieldInfo
 
 def _fix_unit_ordering(unit):
     if isinstance(unit[0], str):
diff --git a/yt/frontends/gadget/fields.py b/yt/frontends/gadget/fields.py
index a07db06bcfe..f315179949d 100644
--- a/yt/frontends/gadget/fields.py
+++ b/yt/frontends/gadget/fields.py
@@ -1,7 +1,6 @@
 from yt.frontends.sph.fields import SPHFieldInfo
-from yt.utilities.physical_constants import mp, kb
-from yt.utilities.physical_ratios import \
-    _primordial_mass_fraction
+from yt.utilities.physical_constants import kb, mp
+from yt.utilities.physical_ratios import _primordial_mass_fraction
 
 
 class GadgetFieldInfo(SPHFieldInfo):
diff --git a/yt/frontends/gadget/io.py b/yt/frontends/gadget/io.py
index 2b2ac4da678..60aa68b3f21 100644
--- a/yt/frontends/gadget/io.py
+++ b/yt/frontends/gadget/io.py
@@ -1,14 +1,12 @@
-import numpy as np
 import os
 
-from yt.frontends.sph.io import \
-    IOHandlerSPH
+import numpy as np
+
+from yt.frontends.sph.io import IOHandlerSPH
 from yt.utilities.logger import ytLogger as mylog
 from yt.utilities.on_demand_imports import _h5py as h5py
 
-from .definitions import \
-    gadget_hdf5_ptypes, \
-    SNAP_FORMAT_2_OFFSET
+from .definitions import SNAP_FORMAT_2_OFFSET, gadget_hdf5_ptypes
 
 
 class IOHandlerGadgetHDF5(IOHandlerSPH):
diff --git a/yt/frontends/gadget/simulation_handling.py b/yt/frontends/gadget/simulation_handling.py
index f2de24db014..38d8e9b5a73 100644
--- a/yt/frontends/gadget/simulation_handling.py
+++ b/yt/frontends/gadget/simulation_handling.py
@@ -1,31 +1,23 @@
-import numpy as np
 import glob
 import os
 
-from unyt import \
-    dimensions, \
-    unyt_array
-from unyt.unit_registry import \
-    UnitRegistry
-
-from yt.convenience import \
-    load
-from yt.funcs import \
-    only_on_root
-from yt.data_objects.time_series import \
-    SimulationTimeSeries, DatasetSeries
-from yt.utilities.cosmology import \
-    Cosmology
-from yt.utilities.exceptions import \
-    InvalidSimulationTimeSeries, \
-    MissingParameter, \
-    NoStoppingCondition
-from yt.utilities.exceptions import \
-    YTOutputNotIdentified
-from yt.utilities.logger import ytLogger as \
-    mylog
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_objects
+import numpy as np
+from unyt import dimensions, unyt_array
+from unyt.unit_registry import UnitRegistry
+
+from yt.convenience import load
+from yt.data_objects.time_series import DatasetSeries, SimulationTimeSeries
+from yt.funcs import only_on_root
+from yt.utilities.cosmology import Cosmology
+from yt.utilities.exceptions import (
+    InvalidSimulationTimeSeries,
+    MissingParameter,
+    NoStoppingCondition,
+    YTOutputNotIdentified,
+)
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.parallel_tools.parallel_analysis_interface import parallel_objects
+
 
 class GadgetSimulation(SimulationTimeSeries):
     r"""
diff --git a/yt/frontends/gadget/testing.py b/yt/frontends/gadget/testing.py
index bfdd9429ad1..e8c9906a524 100644
--- a/yt/frontends/gadget/testing.py
+++ b/yt/frontends/gadget/testing.py
@@ -1,16 +1,9 @@
 import numpy as np
 
-from .definitions import (
-    gadget_field_specs,
-    gadget_ptype_specs,
-)
-from .data_structures import (
-    GadgetBinaryHeader,
-    GadgetDataset,
-)
+from .data_structures import GadgetBinaryHeader, GadgetDataset
+from .definitions import gadget_field_specs, gadget_ptype_specs
 from .io import IOHandlerGadgetBinary
 
-
 vector_fields = dict(IOHandlerGadgetBinary._vector_fields)
 
 block_ids = {
diff --git a/yt/frontends/gadget/tests/test_outputs.py b/yt/frontends/gadget/tests/test_outputs.py
index d9007800ed9..6da03780fa7 100644
--- a/yt/frontends/gadget/tests/test_outputs.py
+++ b/yt/frontends/gadget/tests/test_outputs.py
@@ -1,18 +1,14 @@
-from collections import OrderedDict
-from itertools import product
 import os
 import shutil
 import tempfile
+from collections import OrderedDict
+from itertools import product
 
 import yt
-from yt.testing import requires_file, \
-    ParticleSelectionComparison
-from yt.utilities.answer_testing.framework import \
-    data_dir_load, \
-    requires_ds, \
-    sph_answer
-from yt.frontends.gadget.api import GadgetHDF5Dataset, GadgetDataset
+from yt.frontends.gadget.api import GadgetDataset, GadgetHDF5Dataset
 from yt.frontends.gadget.testing import fake_gadget_binary
+from yt.testing import ParticleSelectionComparison, requires_file
+from yt.utilities.answer_testing.framework import data_dir_load, requires_ds, sph_answer
 
 isothermal_h5 = "IsothermalCollapse/snap_505.hdf5"
 isothermal_bin = "IsothermalCollapse/snap_505"
@@ -127,4 +123,3 @@ def test_bigendian_field_access():
     ds = data_dir_load(BE_Gadget)
     data = ds.all_data()
     data['Halo', 'Velocities']
-
diff --git a/yt/frontends/gadget_fof/__init__.py b/yt/frontends/gadget_fof/__init__.py
index 04ebe5cd2d7..46e4642cc5d 100644
--- a/yt/frontends/gadget_fof/__init__.py
+++ b/yt/frontends/gadget_fof/__init__.py
@@ -5,4 +5,3 @@
 
 
 """
-
diff --git a/yt/frontends/gadget_fof/api.py b/yt/frontends/gadget_fof/api.py
index 465953f811c..02e041fa7a4 100644
--- a/yt/frontends/gadget_fof/api.py
+++ b/yt/frontends/gadget_fof/api.py
@@ -1,17 +1,11 @@
-from .data_structures import \
-    GadgetFOFParticleIndex, \
-    GadgetFOFHDF5File, \
-    GadgetFOFDataset, \
-    GadgetFOFHaloParticleIndex, \
-    GadgetFOFHaloDataset, \
-    GagdetFOFHaloContainer
-
-from .io import \
-    IOHandlerGadgetFOFHDF5, \
-    IOHandlerGadgetFOFHaloHDF5
-
-from .fields import \
-    GadgetFOFFieldInfo, \
-    GadgetFOFHaloFieldInfo
-
 from . import tests
+from .data_structures import (
+    GadgetFOFDataset,
+    GadgetFOFHaloDataset,
+    GadgetFOFHaloParticleIndex,
+    GadgetFOFHDF5File,
+    GadgetFOFParticleIndex,
+    GagdetFOFHaloContainer,
+)
+from .fields import GadgetFOFFieldInfo, GadgetFOFHaloFieldInfo
+from .io import IOHandlerGadgetFOFHaloHDF5, IOHandlerGadgetFOFHDF5
diff --git a/yt/frontends/gadget_fof/data_structures.py b/yt/frontends/gadget_fof/data_structures.py
index 26c3ff4bbed..ff75954d647 100644
--- a/yt/frontends/gadget_fof/data_structures.py
+++ b/yt/frontends/gadget_fof/data_structures.py
@@ -1,30 +1,21 @@
+import os
+import weakref
 from collections import defaultdict
 from functools import partial
-from yt.utilities.on_demand_imports import _h5py as h5py
+
 import numpy as np
-import os
-import weakref
 
-from yt.data_objects.data_containers import \
-    YTSelectionContainer
-from yt.data_objects.static_output import \
-    ParticleDataset
-from yt.frontends.gadget.data_structures import \
-    _fix_unit_ordering
-from yt.frontends.gadget_fof.fields import \
-    GadgetFOFFieldInfo, \
-    GadgetFOFHaloFieldInfo
-from yt.frontends.halo_catalog.data_structures import \
-    HaloCatalogFile
-from yt.funcs import \
-    only_on_root, \
-    setdefaultattr
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
-from yt.utilities.cosmology import \
-    Cosmology
-from yt.utilities.logger import ytLogger as \
-    mylog
+from yt.data_objects.data_containers import YTSelectionContainer
+from yt.data_objects.static_output import ParticleDataset
+from yt.frontends.gadget.data_structures import _fix_unit_ordering
+from yt.frontends.gadget_fof.fields import GadgetFOFFieldInfo, GadgetFOFHaloFieldInfo
+from yt.frontends.halo_catalog.data_structures import HaloCatalogFile
+from yt.funcs import only_on_root, setdefaultattr
+from yt.geometry.particle_geometry_handler import ParticleIndex
+from yt.utilities.cosmology import Cosmology
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.on_demand_imports import _h5py as h5py
+
 
 class GadgetFOFParticleIndex(ParticleIndex):
     def _calculate_particle_count(self):
diff --git a/yt/frontends/gadget_fof/fields.py b/yt/frontends/gadget_fof/fields.py
index 9535a83e9e9..454f620f77b 100644
--- a/yt/frontends/gadget_fof/fields.py
+++ b/yt/frontends/gadget_fof/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 m_units = "code_mass"
 p_units = "code_length"
diff --git a/yt/frontends/gadget_fof/io.py b/yt/frontends/gadget_fof/io.py
index 213ac253343..6f734212e14 100644
--- a/yt/frontends/gadget_fof/io.py
+++ b/yt/frontends/gadget_fof/io.py
@@ -1,14 +1,13 @@
 from collections import defaultdict
-from yt.utilities.on_demand_imports import _h5py as h5py
+
 import numpy as np
 
 from yt.funcs import mylog
-from yt.utilities.exceptions import \
-    YTDomainOverflow
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.utilities.lib.geometry_utils import \
-    compute_morton
+from yt.utilities.exceptions import YTDomainOverflow
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.lib.geometry_utils import compute_morton
+from yt.utilities.on_demand_imports import _h5py as h5py
+
 
 class IOHandlerGadgetFOFHDF5(BaseIOHandler):
     _dataset_type = "gadget_fof_hdf5"
diff --git a/yt/frontends/gadget_fof/tests/test_outputs.py b/yt/frontends/gadget_fof/tests/test_outputs.py
index 8d82072f068..0a9445ed369 100644
--- a/yt/frontends/gadget_fof/tests/test_outputs.py
+++ b/yt/frontends/gadget_fof/tests/test_outputs.py
@@ -1,16 +1,17 @@
 import numpy as np
 
-from yt.frontends.gadget_fof.api import \
-    GadgetFOFDataset
-from yt.testing import \
-    requires_file, \
-    assert_equal, \
-    assert_array_equal, \
-    ParticleSelectionComparison
-from yt.utilities.answer_testing.framework import \
-    FieldValuesTest, \
-    requires_ds, \
-    data_dir_load
+from yt.frontends.gadget_fof.api import GadgetFOFDataset
+from yt.testing import (
+    ParticleSelectionComparison,
+    assert_array_equal,
+    assert_equal,
+    requires_file,
+)
+from yt.utilities.answer_testing.framework import (
+    FieldValuesTest,
+    data_dir_load,
+    requires_ds,
+)
 
 _fields = ("particle_position_x", "particle_position_y",
            "particle_position_z", "particle_velocity_x",
diff --git a/yt/frontends/gamer/__init__.py b/yt/frontends/gamer/__init__.py
index 6761e2147af..9686aa19db2 100644
--- a/yt/frontends/gamer/__init__.py
+++ b/yt/frontends/gamer/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/gamer/api.py b/yt/frontends/gamer/api.py
index 8c0724c80e5..8ad4e50d410 100644
--- a/yt/frontends/gamer/api.py
+++ b/yt/frontends/gamer/api.py
@@ -1,13 +1,6 @@
-from .data_structures import \
-      GAMERGrid, \
-      GAMERHierarchy, \
-      GAMERDataset
-
-from .fields import \
-      GAMERFieldInfo
-
-from .io import \
-      IOHandlerGAMER
+from .data_structures import GAMERDataset, GAMERGrid, GAMERHierarchy
+from .fields import GAMERFieldInfo
+from .io import IOHandlerGAMER
 
 ### NOT SUPPORTED YET
 #from . import tests
diff --git a/yt/frontends/gamer/data_structures.py b/yt/frontends/gamer/data_structures.py
index e629b23f3e2..9d91a9c2cb3 100644
--- a/yt/frontends/gamer/data_structures.py
+++ b/yt/frontends/gamer/data_structures.py
@@ -1,21 +1,16 @@
 import os
-import numpy as np
 import weakref
 
-from yt.funcs import \
-    mylog, \
-    setdefaultattr
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.data_objects.static_output import \
-    Dataset
-from yt.utilities.file_handler import \
-    HDF5FileHandler
-from .fields import GAMERFieldInfo
-from .definitions import geometry_parameters
+import numpy as np
 
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset
+from yt.funcs import mylog, setdefaultattr
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.utilities.file_handler import HDF5FileHandler
+
+from .definitions import geometry_parameters
+from .fields import GAMERFieldInfo
 
 
 class GAMERGrid(AMRGridPatch):
diff --git a/yt/frontends/gamer/fields.py b/yt/frontends/gamer/fields.py
index be330231f08..9e33f5b5e51 100644
--- a/yt/frontends/gamer/fields.py
+++ b/yt/frontends/gamer/fields.py
@@ -1,5 +1,5 @@
 from yt.fields.field_info_container import FieldInfoContainer
-from yt.utilities.physical_constants import mh, kb
+from yt.utilities.physical_constants import kb, mh
 
 b_units   = "code_magnetic"
 pre_units = "code_mass / (code_length*code_time**2)"
diff --git a/yt/frontends/gamer/io.py b/yt/frontends/gamer/io.py
index e2b6a9f218e..f2b9af02125 100644
--- a/yt/frontends/gamer/io.py
+++ b/yt/frontends/gamer/io.py
@@ -1,11 +1,10 @@
-import numpy as np
 from itertools import groupby
 
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.utilities.logger import ytLogger as mylog
-from yt.geometry.selection_routines import AlwaysSelector
+import numpy as np
 
+from yt.geometry.selection_routines import AlwaysSelector
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.logger import ytLogger as mylog
 
 #-----------------------------------------------------------------------------
 # GAMER shares a similar HDF5 format, and thus io.py as well, with FLASH
diff --git a/yt/frontends/gamer/tests/test_outputs.py b/yt/frontends/gamer/tests/test_outputs.py
index e28e8f6a0db..7ebb89c6a10 100644
--- a/yt/frontends/gamer/tests/test_outputs.py
+++ b/yt/frontends/gamer/tests/test_outputs.py
@@ -1,14 +1,10 @@
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    units_override_check
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    small_patch_amr, \
-    data_dir_load
 from yt.frontends.gamer.api import GAMERDataset
-
-
+from yt.testing import assert_equal, requires_file, units_override_check
+from yt.utilities.answer_testing.framework import (
+    data_dir_load,
+    requires_ds,
+    small_patch_amr,
+)
 
 jet         = "InteractingJets/jet_000002"
 _fields_jet = ("temperature", "density", "velocity_magnitude")
diff --git a/yt/frontends/gdf/api.py b/yt/frontends/gdf/api.py
index 99b4205d6f4..682c31a697a 100644
--- a/yt/frontends/gdf/api.py
+++ b/yt/frontends/gdf/api.py
@@ -1,13 +1,6 @@
-from .data_structures import \
-      GDFGrid, \
-      GDFHierarchy, \
-      GDFDataset
+from . import tests
+from .data_structures import GDFDataset, GDFGrid, GDFHierarchy
+from .fields import GDFFieldInfo
+from .io import IOHandlerGDFHDF5
 
-from .fields import \
-      GDFFieldInfo
 add_gdf_field = GDFFieldInfo.add_field
-
-from .io import \
-      IOHandlerGDFHDF5
-
-from . import tests
diff --git a/yt/frontends/gdf/data_structures.py b/yt/frontends/gdf/data_structures.py
index 9fb6b3a8614..5281f14ec29 100644
--- a/yt/frontends/gdf/data_structures.py
+++ b/yt/frontends/gdf/data_structures.py
@@ -1,30 +1,21 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
-import numpy as np
-import weakref
 import os
-from yt.funcs import \
-    ensure_tuple, \
-    just_one, \
-    setdefaultattr
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.data_objects.static_output import \
-    Dataset
-from yt.units.dimensions import \
-    dimensionless as sympy_one
-from yt.units.unit_object import \
-    Unit
-from yt.units.unit_systems import \
-    unit_system_registry
-from yt.utilities.exceptions import \
-    YTGDFUnknownGeometry
-from yt.utilities.lib.misc_utilities import \
-    get_box_grids_level
+import weakref
+
+import numpy as np
+
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.static_output import Dataset
+from yt.funcs import ensure_tuple, just_one, setdefaultattr
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.units.dimensions import dimensionless as sympy_one
+from yt.units.unit_object import Unit
+from yt.units.unit_systems import unit_system_registry
+from yt.utilities.exceptions import YTGDFUnknownGeometry
+from yt.utilities.lib.misc_utilities import get_box_grids_level
 from yt.utilities.logger import ytLogger as mylog
-from .fields import GDFFieldInfo
+from yt.utilities.on_demand_imports import _h5py as h5py
 
+from .fields import GDFFieldInfo
 
 GEOMETRY_TRANS = {
     0: "cartesian",
diff --git a/yt/frontends/gdf/definitions.py b/yt/frontends/gdf/definitions.py
index 307b63a9616..70a2797752a 100644
--- a/yt/frontends/gdf/definitions.py
+++ b/yt/frontends/gdf/definitions.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/gdf/fields.py b/yt/frontends/gdf/fields.py
index de065bd4605..fdb5ce7270f 100644
--- a/yt/frontends/gdf/fields.py
+++ b/yt/frontends/gdf/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 # The nice thing about GDF is that for the most part, everything is in CGS,
 # with potentially a scalar modification.
diff --git a/yt/frontends/gdf/io.py b/yt/frontends/gdf/io.py
index 7912d3be992..308ff566601 100644
--- a/yt/frontends/gdf/io.py
+++ b/yt/frontends/gdf/io.py
@@ -1,10 +1,9 @@
 import numpy as np
-from yt.utilities.on_demand_imports import _h5py as h5py
-from yt.funcs import \
-    mylog
+
+from yt.funcs import mylog
 from yt.geometry.selection_routines import GridSelector
-from yt.utilities.io_handler import \
-    BaseIOHandler
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.on_demand_imports import _h5py as h5py
 
 
 def _grid_dname(grid_id):
diff --git a/yt/frontends/gdf/tests/test_outputs.py b/yt/frontends/gdf/tests/test_outputs.py
index 649ca9e08ab..a20d530b3c8 100644
--- a/yt/frontends/gdf/tests/test_outputs.py
+++ b/yt/frontends/gdf/tests/test_outputs.py
@@ -1,12 +1,10 @@
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    units_override_check
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    small_patch_amr, \
-    data_dir_load
 from yt.frontends.gdf.api import GDFDataset
+from yt.testing import assert_equal, requires_file, units_override_check
+from yt.utilities.answer_testing.framework import (
+    data_dir_load,
+    requires_ds,
+    small_patch_amr,
+)
 
 _fields = ("density", "velocity_x")
 
diff --git a/yt/frontends/gizmo/api.py b/yt/frontends/gizmo/api.py
index 1c2f1becf02..bad1f564a00 100644
--- a/yt/frontends/gizmo/api.py
+++ b/yt/frontends/gizmo/api.py
@@ -1,5 +1,2 @@
-from .data_structures import \
-    GizmoDataset
-
-from .fields import \
-    GizmoFieldInfo
+from .data_structures import GizmoDataset
+from .fields import GizmoFieldInfo
diff --git a/yt/frontends/gizmo/data_structures.py b/yt/frontends/gizmo/data_structures.py
index d4f4a22f59a..06c3f7da807 100644
--- a/yt/frontends/gizmo/data_structures.py
+++ b/yt/frontends/gizmo/data_structures.py
@@ -1,12 +1,9 @@
 import os
 
+from yt.frontends.gadget.data_structures import GadgetHDF5Dataset
 from yt.utilities.on_demand_imports import _h5py as h5py
 
-from yt.frontends.gadget.data_structures import \
-    GadgetHDF5Dataset
-
-from .fields import \
-    GizmoFieldInfo
+from .fields import GizmoFieldInfo
 
 
 class GizmoDataset(GadgetHDF5Dataset):
diff --git a/yt/frontends/gizmo/fields.py b/yt/frontends/gizmo/fields.py
index cb9d23b2c97..43e7fda39e8 100644
--- a/yt/frontends/gizmo/fields.py
+++ b/yt/frontends/gizmo/fields.py
@@ -1,14 +1,8 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
-from yt.fields.magnetic_field import \
-    setup_magnetic_field_aliases
-from yt.fields.species_fields import \
-    add_species_field_by_density, \
-    setup_species_fields
-from yt.frontends.gadget.fields import \
-    GadgetFieldInfo
-from yt.frontends.sph.fields import \
-    SPHFieldInfo
+from yt.fields.field_info_container import FieldInfoContainer
+from yt.fields.magnetic_field import setup_magnetic_field_aliases
+from yt.fields.species_fields import add_species_field_by_density, setup_species_fields
+from yt.frontends.gadget.fields import GadgetFieldInfo
+from yt.frontends.sph.fields import SPHFieldInfo
 
 metal_elements = ["He", "C", "N", "O", "Ne",
                   "Mg", "Si", "S", "Ca", "Fe"]
diff --git a/yt/frontends/gizmo/tests/test_outputs.py b/yt/frontends/gizmo/tests/test_outputs.py
index 043900ec29a..b20493d8dc6 100644
--- a/yt/frontends/gizmo/tests/test_outputs.py
+++ b/yt/frontends/gizmo/tests/test_outputs.py
@@ -1,14 +1,10 @@
 from collections import OrderedDict
 
 import yt
-from yt.testing import \
-    requires_file
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    sph_answer
 from yt.frontends.gizmo.api import GizmoDataset
 from yt.frontends.gizmo.fields import metal_elements
-
+from yt.testing import requires_file
+from yt.utilities.answer_testing.framework import requires_ds, sph_answer
 
 # This maps from field names to weight field names to use for projections
 fields = OrderedDict(
diff --git a/yt/frontends/halo_catalog/__init__.py b/yt/frontends/halo_catalog/__init__.py
index 04ebe5cd2d7..46e4642cc5d 100644
--- a/yt/frontends/halo_catalog/__init__.py
+++ b/yt/frontends/halo_catalog/__init__.py
@@ -5,4 +5,3 @@
 
 
 """
-
diff --git a/yt/frontends/halo_catalog/api.py b/yt/frontends/halo_catalog/api.py
index e647bc11327..93deea97d16 100644
--- a/yt/frontends/halo_catalog/api.py
+++ b/yt/frontends/halo_catalog/api.py
@@ -1,8 +1,3 @@
-from .data_structures import \
-     HaloCatalogDataset
-
-from .io import \
-     IOHandlerHaloCatalogHDF5
-
-from .fields import \
-     HaloCatalogFieldInfo
+from .data_structures import HaloCatalogDataset
+from .fields import HaloCatalogFieldInfo
+from .io import IOHandlerHaloCatalogHDF5
diff --git a/yt/frontends/halo_catalog/data_structures.py b/yt/frontends/halo_catalog/data_structures.py
index a26f9f1f086..8e3abc1363c 100644
--- a/yt/frontends/halo_catalog/data_structures.py
+++ b/yt/frontends/halo_catalog/data_structures.py
@@ -1,18 +1,15 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
-import numpy as np
 import glob
 
-from .fields import \
-    HaloCatalogFieldInfo
-
-from yt.frontends.ytdata.data_structures import \
-    SavedDataset
-from yt.funcs import \
-    parse_h5_attr
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
-from yt.data_objects.static_output import \
-    ParticleFile
+import numpy as np
+
+from yt.data_objects.static_output import ParticleFile
+from yt.frontends.ytdata.data_structures import SavedDataset
+from yt.funcs import parse_h5_attr
+from yt.geometry.particle_geometry_handler import ParticleIndex
+from yt.utilities.on_demand_imports import _h5py as h5py
+
+from .fields import HaloCatalogFieldInfo
+
 
 class HaloCatalogParticleIndex(ParticleIndex):
     def _setup_filenames(self):
diff --git a/yt/frontends/halo_catalog/fields.py b/yt/frontends/halo_catalog/fields.py
index d25dc8f44cc..d0732f8cd9d 100644
--- a/yt/frontends/halo_catalog/fields.py
+++ b/yt/frontends/halo_catalog/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 m_units = "g"
 p_units = "cm"
diff --git a/yt/frontends/halo_catalog/io.py b/yt/frontends/halo_catalog/io.py
index d16d5a1c703..4bc7821d61f 100644
--- a/yt/frontends/halo_catalog/io.py
+++ b/yt/frontends/halo_catalog/io.py
@@ -1,15 +1,11 @@
 import numpy as np
 
-from yt.funcs import \
-    mylog, \
-    parse_h5_attr
-from yt.units.yt_array import \
-    uvstack
-from yt.utilities.on_demand_imports import _h5py as h5py
+from yt.funcs import mylog, parse_h5_attr
+from yt.units.yt_array import uvstack
 from yt.utilities.exceptions import YTDomainOverflow
-from yt.utilities.io_handler import \
-    BaseIOHandler
+from yt.utilities.io_handler import BaseIOHandler
 from yt.utilities.lib.geometry_utils import compute_morton
+from yt.utilities.on_demand_imports import _h5py as h5py
 
 
 class IOHandlerHaloCatalogHDF5(BaseIOHandler):
diff --git a/yt/frontends/halo_catalog/tests/test_outputs.py b/yt/frontends/halo_catalog/tests/test_outputs.py
index 3562812f0f2..e235be7765e 100644
--- a/yt/frontends/halo_catalog/tests/test_outputs.py
+++ b/yt/frontends/halo_catalog/tests/test_outputs.py
@@ -1,18 +1,11 @@
 import numpy as np
 
-from yt.convenience import \
-    load as yt_load
-from yt.frontends.halo_catalog.data_structures import \
-    HaloCatalogDataset
-from yt.frontends.ytdata.utilities import \
-    save_as_dataset
-from yt.testing import \
-    assert_array_equal, \
-    requires_module, \
-    TempDirTest
-from yt.units.yt_array import \
-    YTArray, \
-    YTQuantity
+from yt.convenience import load as yt_load
+from yt.frontends.halo_catalog.data_structures import HaloCatalogDataset
+from yt.frontends.ytdata.utilities import save_as_dataset
+from yt.testing import TempDirTest, assert_array_equal, requires_module
+from yt.units.yt_array import YTArray, YTQuantity
+
 
 def fake_halo_catalog(data):
     filename = "catalog.0.h5"
diff --git a/yt/frontends/http_stream/api.py b/yt/frontends/http_stream/api.py
index 554845f7414..bf1851777a6 100644
--- a/yt/frontends/http_stream/api.py
+++ b/yt/frontends/http_stream/api.py
@@ -1,5 +1,2 @@
-from .data_structures import \
-    HTTPStreamDataset
-
-from .io import \
-    IOHandlerHTTPStream
+from .data_structures import HTTPStreamDataset
+from .io import IOHandlerHTTPStream
diff --git a/yt/frontends/http_stream/data_structures.py b/yt/frontends/http_stream/data_structures.py
index 3eff4bc0cba..a0ccf776d7f 100644
--- a/yt/frontends/http_stream/data_structures.py
+++ b/yt/frontends/http_stream/data_structures.py
@@ -1,16 +1,13 @@
 import json
-import numpy as np
 import time
 
-from yt.data_objects.static_output import \
-    ParticleDataset, \
-    ParticleFile
-from yt.frontends.sph.fields import \
-    SPHFieldInfo
-from yt.funcs import \
-    get_requests
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
+import numpy as np
+
+from yt.data_objects.static_output import ParticleDataset, ParticleFile
+from yt.frontends.sph.fields import SPHFieldInfo
+from yt.funcs import get_requests
+from yt.geometry.particle_geometry_handler import ParticleIndex
+
 
 class HTTPParticleFile(ParticleFile):
     pass
diff --git a/yt/frontends/http_stream/io.py b/yt/frontends/http_stream/io.py
index 8653d693cf6..c6533d1ca4c 100644
--- a/yt/frontends/http_stream/io.py
+++ b/yt/frontends/http_stream/io.py
@@ -1,12 +1,9 @@
 import numpy as np
 
-from yt.funcs import \
-    get_requests, \
-    mylog
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.utilities.lib.geometry_utils import \
-    compute_morton
+from yt.funcs import get_requests, mylog
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.lib.geometry_utils import compute_morton
+
 
 class IOHandlerHTTPStream(BaseIOHandler):
     _dataset_type = "http_particle_stream"
diff --git a/yt/frontends/moab/__init__.py b/yt/frontends/moab/__init__.py
index fcc280c5b40..3a67715b31b 100644
--- a/yt/frontends/moab/__init__.py
+++ b/yt/frontends/moab/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/moab/api.py b/yt/frontends/moab/api.py
index eaf37635ec4..d932dbcf0e0 100644
--- a/yt/frontends/moab/api.py
+++ b/yt/frontends/moab/api.py
@@ -1,14 +1,9 @@
-from .data_structures import \
-      MoabHex8Mesh, \
-      MoabHex8Hierarchy, \
-      MoabHex8Dataset, \
-      PyneMoabHex8Dataset
-
-from .fields import \
-      MoabFieldInfo, \
-      PyneFieldInfo
-
-from .io import \
-      IOHandlerMoabH5MHex8
-
 from . import tests
+from .data_structures import (
+    MoabHex8Dataset,
+    MoabHex8Hierarchy,
+    MoabHex8Mesh,
+    PyneMoabHex8Dataset,
+)
+from .fields import MoabFieldInfo, PyneFieldInfo
+from .io import IOHandlerMoabH5MHex8
diff --git a/yt/frontends/moab/data_structures.py b/yt/frontends/moab/data_structures.py
index 59b455d7ff7..3387ec54307 100644
--- a/yt/frontends/moab/data_structures.py
+++ b/yt/frontends/moab/data_structures.py
@@ -1,19 +1,18 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
 import os
-import numpy as np
 import weakref
-from yt.data_objects.unstructured_mesh import \
-    SemiStructuredMesh
-from yt.funcs import \
-    setdefaultattr
-from yt.geometry.unstructured_mesh_handler import \
-    UnstructuredIndex
-from yt.data_objects.static_output import \
-    Dataset
+
+import numpy as np
+
+from yt.data_objects.static_output import Dataset
+from yt.data_objects.unstructured_mesh import SemiStructuredMesh
+from yt.funcs import setdefaultattr
+from yt.geometry.unstructured_mesh_handler import UnstructuredIndex
 from yt.utilities.file_handler import HDF5FileHandler
+from yt.utilities.on_demand_imports import _h5py as h5py
 
 from .fields import MoabFieldInfo, PyneFieldInfo
 
+
 class MoabHex8Mesh(SemiStructuredMesh):
     _connectivity_length = 8
     _index_offset = 1
@@ -177,4 +176,3 @@ def _is_valid(self, *args, **kwargs):
 
     def __repr__(self):
         return self.basename.rsplit(".", 1)[0]
-
diff --git a/yt/frontends/moab/definitions.py b/yt/frontends/moab/definitions.py
index 8b137891791..e69de29bb2d 100644
--- a/yt/frontends/moab/definitions.py
+++ b/yt/frontends/moab/definitions.py
@@ -1 +0,0 @@
-
diff --git a/yt/frontends/moab/fields.py b/yt/frontends/moab/fields.py
index 2a3190fc731..90cb53d7be3 100644
--- a/yt/frontends/moab/fields.py
+++ b/yt/frontends/moab/fields.py
@@ -1,5 +1,5 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
+
 
 class MoabFieldInfo(FieldInfoContainer):
     pass
diff --git a/yt/frontends/moab/io.py b/yt/frontends/moab/io.py
index 3303b7fe851..12b883cc23e 100644
--- a/yt/frontends/moab/io.py
+++ b/yt/frontends/moab/io.py
@@ -1,4 +1,5 @@
 import numpy as np
+
 from yt.funcs import mylog
 from yt.utilities.io_handler import BaseIOHandler
 
diff --git a/yt/frontends/moab/tests/test_c5.py b/yt/frontends/moab/tests/test_c5.py
index 1c9d0b674a2..706cb203ce9 100644
--- a/yt/frontends/moab/tests/test_c5.py
+++ b/yt/frontends/moab/tests/test_c5.py
@@ -1,15 +1,17 @@
 import numpy as np
 
-from yt.testing import \
-    assert_equal, \
-    assert_almost_equal, \
-    requires_file, \
-    units_override_check
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load, \
-    FieldValuesTest
 from yt.frontends.moab.api import MoabHex8Dataset
+from yt.testing import (
+    assert_almost_equal,
+    assert_equal,
+    requires_file,
+    units_override_check,
+)
+from yt.utilities.answer_testing.framework import (
+    FieldValuesTest,
+    data_dir_load,
+    requires_ds,
+)
 
 _fields = (("moab", "flux"),
           )
diff --git a/yt/frontends/open_pmd/__init__.py b/yt/frontends/open_pmd/__init__.py
index 2c656b643d4..dcdf43a9dfd 100644
--- a/yt/frontends/open_pmd/__init__.py
+++ b/yt/frontends/open_pmd/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/open_pmd/api.py b/yt/frontends/open_pmd/api.py
index cfb0979e774..851f7bb94b2 100644
--- a/yt/frontends/open_pmd/api.py
+++ b/yt/frontends/open_pmd/api.py
@@ -1,13 +1,4 @@
-from .data_structures import \
-    OpenPMDDataset, \
-    OpenPMDGrid, \
-    OpenPMDHierarchy
-
-from .fields import \
-    OpenPMDFieldInfo
-
-from .io import \
-    IOHandlerOpenPMDHDF5
-
-from . import \
-    tests
+from . import tests
+from .data_structures import OpenPMDDataset, OpenPMDGrid, OpenPMDHierarchy
+from .fields import OpenPMDFieldInfo
+from .io import IOHandlerOpenPMDHDF5
diff --git a/yt/frontends/open_pmd/data_structures.py b/yt/frontends/open_pmd/data_structures.py
index 2cd0e6d1d0e..d6556c3ef8a 100644
--- a/yt/frontends/open_pmd/data_structures.py
+++ b/yt/frontends/open_pmd/data_structures.py
@@ -1,23 +1,19 @@
 from distutils.version import StrictVersion
 from functools import reduce
 from operator import mul
-from os import \
-    path, \
-    listdir
+from os import listdir, path
 from re import match
 
 import numpy as np
+
 from yt.data_objects.grid_patch import AMRGridPatch
 from yt.data_objects.static_output import Dataset
 from yt.data_objects.time_series import DatasetSeries
 from yt.frontends.open_pmd.fields import OpenPMDFieldInfo
-from yt.frontends.open_pmd.misc import \
-    is_const_component, \
-    get_component
+from yt.frontends.open_pmd.misc import get_component, is_const_component
 from yt.funcs import setdefaultattr
 from yt.geometry.grid_geometry_handler import GridIndex
-from yt.utilities.file_handler import HDF5FileHandler, \
-    warn_h5py
+from yt.utilities.file_handler import HDF5FileHandler, warn_h5py
 from yt.utilities.logger import ytLogger as mylog
 from yt.utilities.on_demand_imports import _h5py as h5
 
@@ -616,4 +612,3 @@ def _is_valid(self, *args, **kwargs):
                 return False
         except (IOError, OSError, ImportError):
             return False
-
diff --git a/yt/frontends/open_pmd/fields.py b/yt/frontends/open_pmd/fields.py
index 71a47ed2975..8f5f798dc64 100644
--- a/yt/frontends/open_pmd/fields.py
+++ b/yt/frontends/open_pmd/fields.py
@@ -2,15 +2,11 @@
 
 from yt.fields.field_info_container import FieldInfoContainer
 from yt.fields.magnetic_field import setup_magnetic_field_aliases
-from yt.frontends.open_pmd.misc import \
-    parse_unit_dimension, \
-    is_const_component
+from yt.frontends.open_pmd.misc import is_const_component, parse_unit_dimension
 from yt.units.yt_array import YTQuantity
 from yt.utilities.logger import ytLogger as mylog
 from yt.utilities.on_demand_imports import _h5py as h5
-from yt.utilities.physical_constants import \
-    speed_of_light, \
-    mu_0
+from yt.utilities.physical_constants import mu_0, speed_of_light
 
 
 def setup_poynting_vector(self):
diff --git a/yt/frontends/open_pmd/io.py b/yt/frontends/open_pmd/io.py
index fdbc15f6e9f..39ac2c2ca71 100644
--- a/yt/frontends/open_pmd/io.py
+++ b/yt/frontends/open_pmd/io.py
@@ -2,9 +2,7 @@
 
 import numpy as np
 
-from yt.frontends.open_pmd.misc import \
-    is_const_component, \
-    get_component
+from yt.frontends.open_pmd.misc import get_component, is_const_component
 from yt.geometry.selection_routines import GridSelector
 from yt.utilities.io_handler import BaseIOHandler
 
diff --git a/yt/frontends/open_pmd/tests/test_outputs.py b/yt/frontends/open_pmd/tests/test_outputs.py
index 1243f9ca40e..fdbd7f4ebc5 100644
--- a/yt/frontends/open_pmd/tests/test_outputs.py
+++ b/yt/frontends/open_pmd/tests/test_outputs.py
@@ -1,17 +1,17 @@
 from itertools import product
-from yt.frontends.open_pmd.data_structures import \
-    OpenPMDDataset
-from yt.testing import \
-    assert_almost_equal, \
-    assert_equal, \
-    assert_array_equal, \
-    requires_file
-from yt.utilities.answer_testing.framework import \
-    data_dir_load
-from yt.convenience import load
 
 import numpy as np
 
+from yt.convenience import load
+from yt.frontends.open_pmd.data_structures import OpenPMDDataset
+from yt.testing import (
+    assert_almost_equal,
+    assert_array_equal,
+    assert_equal,
+    requires_file,
+)
+from yt.utilities.answer_testing.framework import data_dir_load
+
 twoD = "example-2d/hdf5/data00000100.h5"
 threeD = "example-3d/hdf5/data00000100.h5"
 noFields = "no_fields/data00000400.h5"
@@ -156,4 +156,3 @@ def test_groupBased_out():
         assert ds.current_time <= 1.6499999999999998e-12 * np.ones_like(ds.current_time)
         assert_almost_equal(ds.domain_right_edge - ds.domain_left_edge,
                             domain_width)
-
diff --git a/yt/frontends/owls/api.py b/yt/frontends/owls/api.py
index 2f0b6f38b6b..1819e844da4 100644
--- a/yt/frontends/owls/api.py
+++ b/yt/frontends/owls/api.py
@@ -1,13 +1,5 @@
-from .data_structures import \
-    OWLSDataset
-
-from .fields import \
-    OWLSFieldInfo
-
-from .io import \
-    IOHandlerOWLS
-
-from .simulation_handling import \
-    OWLSSimulation
-    
 from . import tests
+from .data_structures import OWLSDataset
+from .fields import OWLSFieldInfo
+from .io import IOHandlerOWLS
+from .simulation_handling import OWLSSimulation
diff --git a/yt/frontends/owls/data_structures.py b/yt/frontends/owls/data_structures.py
index d0300635d97..fc57a8541f8 100644
--- a/yt/frontends/owls/data_structures.py
+++ b/yt/frontends/owls/data_structures.py
@@ -1,15 +1,12 @@
 import os
 
+import yt.units
+from yt.frontends.gadget.data_structures import GadgetHDF5Dataset
+from yt.utilities.definitions import sec_conversion
 from yt.utilities.on_demand_imports import _h5py as h5py
 
-import yt.units
-from yt.frontends.gadget.data_structures import \
-    GadgetHDF5Dataset
-from yt.utilities.definitions import \
-    sec_conversion
+from .fields import OWLSFieldInfo
 
-from .fields import \
-    OWLSFieldInfo
 
 class OWLSDataset(GadgetHDF5Dataset):
     _particle_mass_name = "Mass"
diff --git a/yt/frontends/owls/fields.py b/yt/frontends/owls/fields.py
index 12601415797..eff036d32ef 100644
--- a/yt/frontends/owls/fields.py
+++ b/yt/frontends/owls/fields.py
@@ -1,15 +1,16 @@
 import os
+
 import numpy as np
-from . import owls_ion_tables as oit
 
-from yt.funcs import \
-    mylog, download_file
 from yt.config import ytcfg
-from yt.fields.species_fields import \
-    add_species_field_by_fraction, \
-    add_species_field_by_density
-from yt.frontends.sph.fields import \
-    SPHFieldInfo
+from yt.fields.species_fields import (
+    add_species_field_by_density,
+    add_species_field_by_fraction,
+)
+from yt.frontends.sph.fields import SPHFieldInfo
+from yt.funcs import download_file, mylog
+
+from . import owls_ion_tables as oit
 
 
 def _get_ion_mass_frac(ion, ftype, itab, data):
diff --git a/yt/frontends/owls/io.py b/yt/frontends/owls/io.py
index dde0eacfbe5..18ce699c1bd 100644
--- a/yt/frontends/owls/io.py
+++ b/yt/frontends/owls/io.py
@@ -1,5 +1,5 @@
-from yt.frontends.gadget.io import \
-    IOHandlerGadgetHDF5
+from yt.frontends.gadget.io import IOHandlerGadgetHDF5
+
 
 class IOHandlerOWLS(IOHandlerGadgetHDF5):
     _dataset_type = "OWLS"
diff --git a/yt/frontends/owls/owls_ion_tables.py b/yt/frontends/owls/owls_ion_tables.py
index b13473c289b..19d3a749010 100644
--- a/yt/frontends/owls/owls_ion_tables.py
+++ b/yt/frontends/owls/owls_ion_tables.py
@@ -1,7 +1,6 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
 import numpy as np
 
-
+from yt.utilities.on_demand_imports import _h5py as h5py
 
 
 def h5rd(fname, path, dtype=None):
diff --git a/yt/frontends/owls/simulation_handling.py b/yt/frontends/owls/simulation_handling.py
index 76ed28a9b30..a84fa68b660 100644
--- a/yt/frontends/owls/simulation_handling.py
+++ b/yt/frontends/owls/simulation_handling.py
@@ -1,7 +1,7 @@
 import os
 
-from yt.frontends.gadget.simulation_handling import \
-    GadgetSimulation
+from yt.frontends.gadget.simulation_handling import GadgetSimulation
+
 
 class OWLSSimulation(GadgetSimulation):
     r"""
diff --git a/yt/frontends/owls/tests/test_outputs.py b/yt/frontends/owls/tests/test_outputs.py
index 78595ce2f10..acbd43bbc9c 100644
--- a/yt/frontends/owls/tests/test_outputs.py
+++ b/yt/frontends/owls/tests/test_outputs.py
@@ -1,14 +1,9 @@
 from collections import OrderedDict
 
-from yt.testing import \
-    requires_file, \
-    ParticleSelectionComparison
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load, \
-    sph_answer
-from yt.frontends.owls.api import OWLSDataset
 from yt.data_objects.particle_filters import add_particle_filter
+from yt.frontends.owls.api import OWLSDataset
+from yt.testing import ParticleSelectionComparison, requires_file
+from yt.utilities.answer_testing.framework import data_dir_load, requires_ds, sph_answer
 
 os33 = "snapshot_033/snap_033.0.hdf5"
 
@@ -52,4 +47,3 @@ def cold_gas(pfilter, data):
 
     mask = (ad['PartType0','Temperature'] <= 1e5)
     assert ad['PartType0','Temperature'][mask].shape == ad['gas_cold','Temperature'].shape
-
diff --git a/yt/frontends/owls_subfind/__init__.py b/yt/frontends/owls_subfind/__init__.py
index 04ebe5cd2d7..46e4642cc5d 100644
--- a/yt/frontends/owls_subfind/__init__.py
+++ b/yt/frontends/owls_subfind/__init__.py
@@ -5,4 +5,3 @@
 
 
 """
-
diff --git a/yt/frontends/owls_subfind/api.py b/yt/frontends/owls_subfind/api.py
index 7168df707bf..035e2c44c0a 100644
--- a/yt/frontends/owls_subfind/api.py
+++ b/yt/frontends/owls_subfind/api.py
@@ -1,10 +1,4 @@
-from .data_structures import \
-     OWLSSubfindDataset
-
-from .io import \
-     IOHandlerOWLSSubfindHDF5
-
-from .fields import \
-     OWLSSubfindFieldInfo
-
 from . import tests
+from .data_structures import OWLSSubfindDataset
+from .fields import OWLSSubfindFieldInfo
+from .io import IOHandlerOWLSSubfindHDF5
diff --git a/yt/frontends/owls_subfind/data_structures.py b/yt/frontends/owls_subfind/data_structures.py
index ea471cc5878..5b3dbd9fe59 100644
--- a/yt/frontends/owls_subfind/data_structures.py
+++ b/yt/frontends/owls_subfind/data_structures.py
@@ -1,26 +1,19 @@
-from collections import defaultdict
-from yt.utilities.on_demand_imports import _h5py as h5py
-import numpy as np
 import glob
 import os
+from collections import defaultdict
+
+import numpy as np
+
+from yt.data_objects.static_output import ParticleDataset, ParticleFile
+from yt.frontends.gadget.data_structures import _fix_unit_ordering
+from yt.funcs import only_on_root, setdefaultattr
+from yt.geometry.particle_geometry_handler import ParticleIndex
+from yt.utilities.exceptions import YTException
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.on_demand_imports import _h5py as h5py
+
+from .fields import OWLSSubfindFieldInfo
 
-from .fields import \
-    OWLSSubfindFieldInfo
-
-from yt.funcs import \
-    only_on_root, \
-    setdefaultattr
-from yt.utilities.exceptions import \
-    YTException
-from yt.utilities.logger import ytLogger as \
-    mylog
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
-from yt.data_objects.static_output import \
-    ParticleDataset, \
-    ParticleFile
-from yt.frontends.gadget.data_structures import \
-    _fix_unit_ordering
 
 class OWLSSubfindParticleIndex(ParticleIndex):
     def __init__(self, ds, dataset_type):
diff --git a/yt/frontends/owls_subfind/fields.py b/yt/frontends/owls_subfind/fields.py
index a41904a8784..18f4a2d8a66 100644
--- a/yt/frontends/owls_subfind/fields.py
+++ b/yt/frontends/owls_subfind/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 m_units = "code_mass"
 mdot_units = "code_mass / code_time"
diff --git a/yt/frontends/owls_subfind/io.py b/yt/frontends/owls_subfind/io.py
index e30e6244884..6ad547d7648 100644
--- a/yt/frontends/owls_subfind/io.py
+++ b/yt/frontends/owls_subfind/io.py
@@ -1,13 +1,11 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
 import numpy as np
 
-from yt.utilities.exceptions import YTDomainOverflow
 from yt.funcs import mylog
-
-from yt.utilities.io_handler import \
-    BaseIOHandler
-
+from yt.utilities.exceptions import YTDomainOverflow
+from yt.utilities.io_handler import BaseIOHandler
 from yt.utilities.lib.geometry_utils import compute_morton
+from yt.utilities.on_demand_imports import _h5py as h5py
+
 
 class IOHandlerOWLSSubfindHDF5(BaseIOHandler):
     _dataset_type = "subfind_hdf5"
diff --git a/yt/frontends/owls_subfind/tests/test_outputs.py b/yt/frontends/owls_subfind/tests/test_outputs.py
index 323a06e5e39..52c010971a1 100644
--- a/yt/frontends/owls_subfind/tests/test_outputs.py
+++ b/yt/frontends/owls_subfind/tests/test_outputs.py
@@ -1,10 +1,12 @@
 import os.path
-from yt.testing import \
-    assert_equal
-from yt.utilities.answer_testing.framework import \
-    FieldValuesTest, \
-    requires_ds, \
-    data_dir_load
+
+from yt.testing import assert_equal
+from yt.utilities.answer_testing.framework import (
+    FieldValuesTest,
+    data_dir_load,
+    requires_ds,
+)
+
 # from yt.frontends.owls_subfind.api import OWLSSubfindDataset
 
 _fields = ("particle_position_x", "particle_position_y",
diff --git a/yt/frontends/ramses/__init__.py b/yt/frontends/ramses/__init__.py
index 1d8841fe239..8016231f3eb 100644
--- a/yt/frontends/ramses/__init__.py
+++ b/yt/frontends/ramses/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/frontends/ramses/api.py b/yt/frontends/ramses/api.py
index b47602b931f..fa20c992924 100644
--- a/yt/frontends/ramses/api.py
+++ b/yt/frontends/ramses/api.py
@@ -1,13 +1,5 @@
-from .data_structures import \
-      RAMSESDataset
-
-from .fields import \
-      RAMSESFieldInfo
-
-from .io import \
-      IOHandlerRAMSES
-
-from .definitions import \
-      field_aliases
-
 from . import tests
+from .data_structures import RAMSESDataset
+from .definitions import field_aliases
+from .fields import RAMSESFieldInfo
+from .io import IOHandlerRAMSES
diff --git a/yt/frontends/ramses/data_structures.py b/yt/frontends/ramses/data_structures.py
index bf1d016f57b..f38c8b8830e 100644
--- a/yt/frontends/ramses/data_structures.py
+++ b/yt/frontends/ramses/data_structures.py
@@ -1,39 +1,30 @@
 import os
-import numpy as np
 import weakref
 from collections import defaultdict
 from glob import glob
 
-from yt.funcs import \
-    mylog, \
-    setdefaultattr
-from yt.geometry.oct_geometry_handler import \
-    OctreeIndex
-from yt.geometry.geometry_handler import \
-    YTDataChunk
-from yt.data_objects.static_output import \
-    Dataset
-from yt.data_objects.octree_subset import \
-    OctreeSubset
-from yt.data_objects.particle_filters import add_particle_filter
+import numpy as np
 
-from yt.utilities.physical_constants import mp, kb
+from yt.arraytypes import blankRecordArray
+from yt.data_objects.octree_subset import OctreeSubset
+from yt.data_objects.particle_filters import add_particle_filter
+from yt.data_objects.static_output import Dataset
+from yt.funcs import mylog, setdefaultattr
+from yt.geometry.geometry_handler import YTDataChunk
+from yt.geometry.oct_container import RAMSESOctreeContainer
+from yt.geometry.oct_geometry_handler import OctreeIndex
+from yt.utilities.cython_fortran_utils import FortranFile as fpu
+from yt.utilities.lib.cosmology_time import friedman
 from yt.utilities.on_demand_imports import _f90nml as f90nml
-from .definitions import ramses_header, field_aliases, particle_families
-from .fields import \
-    RAMSESFieldInfo, _X
+from yt.utilities.physical_constants import kb, mp
+
+from .definitions import field_aliases, particle_families, ramses_header
+from .field_handlers import get_field_handlers
+from .fields import _X, RAMSESFieldInfo
 from .hilbert import get_cpu_list
+from .io_utils import fill_hydro, read_amr
 from .particle_handlers import get_particle_handlers
-from .field_handlers import get_field_handlers
-from yt.utilities.cython_fortran_utils import FortranFile as fpu
-from yt.geometry.oct_container import \
-    RAMSESOctreeContainer
-from yt.arraytypes import blankRecordArray
-
-from yt.utilities.lib.cosmology_time import \
-    friedman
 
-from .io_utils import read_amr, fill_hydro
 
 class RAMSESDomainFile:
     _last_mask = None
diff --git a/yt/frontends/ramses/definitions.py b/yt/frontends/ramses/definitions.py
index 71871bc47f9..5f5fa118b58 100644
--- a/yt/frontends/ramses/definitions.py
+++ b/yt/frontends/ramses/definitions.py
@@ -1,7 +1,9 @@
 # These functions are RAMSES-specific
+import re
+
 from yt.config import ytcfg
 from yt.funcs import mylog
-import re
+
 
 def ramses_header(hvals):
     header = ( ('ncpu', 1, 'i'),
diff --git a/yt/frontends/ramses/field_handlers.py b/yt/frontends/ramses/field_handlers.py
index 4e9e70919b4..162cc4ca53b 100644
--- a/yt/frontends/ramses/field_handlers.py
+++ b/yt/frontends/ramses/field_handlers.py
@@ -1,8 +1,9 @@
-import os
-from yt.utilities.cython_fortran_utils import FortranFile
 import glob
-from yt.funcs import mylog
+import os
+
 from yt.config import ytcfg
+from yt.funcs import mylog
+from yt.utilities.cython_fortran_utils import FortranFile
 
 from .io import _read_fluid_file_descriptor
 from .io_utils import read_offset
diff --git a/yt/frontends/ramses/fields.py b/yt/frontends/ramses/fields.py
index c73efc70047..fa1d32c41da 100644
--- a/yt/frontends/ramses/fields.py
+++ b/yt/frontends/ramses/fields.py
@@ -1,27 +1,22 @@
 import os
+
 import numpy as np
 
 from yt import units
-from yt.fields.field_detector import \
-    FieldDetector
-from yt.fields.field_info_container import \
-    FieldInfoContainer
-from yt.frontends.ramses.io import \
-    convert_ramses_ages
-from yt.funcs import \
-    issue_deprecation_warning
-from yt.utilities.physical_constants import \
-    boltzmann_constant_cgs, \
-    mass_hydrogen_cgs, \
-    mh
-from yt.utilities.linear_interpolators import \
-    BilinearFieldInterpolator
+from yt.fields.field_detector import FieldDetector
+from yt.fields.field_info_container import FieldInfoContainer
+from yt.frontends.ramses.io import convert_ramses_ages
+from yt.funcs import issue_deprecation_warning, mylog
 from yt.utilities.cython_fortran_utils import FortranFile
-from .field_handlers import RTFieldFileHandler
+from yt.utilities.linear_interpolators import BilinearFieldInterpolator
+from yt.utilities.physical_constants import (
+    boltzmann_constant_cgs,
+    mass_hydrogen_cgs,
+    mh,
+    mp,
+)
 
-from yt.utilities.physical_constants import \
-    mp
-from yt.funcs import mylog
+from .field_handlers import RTFieldFileHandler
 
 b_units = "code_magnetic"
 ra_units = "code_length / code_time**2"
diff --git a/yt/frontends/ramses/hilbert.py b/yt/frontends/ramses/hilbert.py
index 9d58d416e7d..68ed6294d64 100644
--- a/yt/frontends/ramses/hilbert.py
+++ b/yt/frontends/ramses/hilbert.py
@@ -1,5 +1,6 @@
 import numpy as np
 
+
 def hilbert3d(X, bit_length):
     '''Compute the order using Hilbert indexing.
 
diff --git a/yt/frontends/ramses/io.py b/yt/frontends/ramses/io.py
index 696e566bcd8..0bd2ec78e42 100644
--- a/yt/frontends/ramses/io.py
+++ b/yt/frontends/ramses/io.py
@@ -1,14 +1,19 @@
 from collections import defaultdict
+
 import numpy as np
 
-from yt.utilities.io_handler import \
-    BaseIOHandler
+from yt.utilities.cython_fortran_utils import FortranFile
+from yt.utilities.exceptions import (
+    YTFieldTypeNotFound,
+    YTFileNotParseable,
+    YTParticleOutputFormatNotImplemented,
+)
+from yt.utilities.io_handler import BaseIOHandler
 from yt.utilities.logger import ytLogger as mylog
 from yt.utilities.physical_ratios import cm_per_km, cm_per_mpc
-from yt.utilities.cython_fortran_utils import FortranFile
-from yt.utilities.exceptions import YTFieldTypeNotFound, YTParticleOutputFormatNotImplemented, \
-    YTFileNotParseable
-from .definitions import VERSION_RE, VAR_DESC_RE
+
+from .definitions import VAR_DESC_RE, VERSION_RE
+
 
 def convert_ramses_ages(ds, conformal_ages):
     tf = ds.t_frw
diff --git a/yt/frontends/ramses/particle_handlers.py b/yt/frontends/ramses/particle_handlers.py
index 0cc1c3154cd..36e45921c84 100644
--- a/yt/frontends/ramses/particle_handlers.py
+++ b/yt/frontends/ramses/particle_handlers.py
@@ -1,7 +1,8 @@
 import os
-from yt.utilities.cython_fortran_utils import FortranFile
-from yt.funcs import mylog
+
 from yt.config import ytcfg
+from yt.funcs import mylog
+from yt.utilities.cython_fortran_utils import FortranFile
 
 from .io import _read_part_file_descriptor
 
diff --git a/yt/frontends/ramses/tests/test_hilbert.py b/yt/frontends/ramses/tests/test_hilbert.py
index dac95279d84..b4bc6f4cb55 100644
--- a/yt/frontends/ramses/tests/test_hilbert.py
+++ b/yt/frontends/ramses/tests/test_hilbert.py
@@ -1,9 +1,9 @@
-from yt.frontends.ramses.hilbert import get_cpu_list, hilbert3d
-from yt.testing import \
-    assert_equal, \
-    requires_file
 import numpy as np
+
 import yt
+from yt.frontends.ramses.hilbert import get_cpu_list, hilbert3d
+from yt.testing import assert_equal, requires_file
+
 
 def test_hilbert3d():
     # 8 different cases, checked against RAMSES' own implementation
diff --git a/yt/frontends/ramses/tests/test_outputs.py b/yt/frontends/ramses/tests/test_outputs.py
index 49437691b47..c6e8db3200f 100644
--- a/yt/frontends/ramses/tests/test_outputs.py
+++ b/yt/frontends/ramses/tests/test_outputs.py
@@ -1,22 +1,26 @@
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    units_override_check, \
-    requires_module
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load, \
-    PixelizedProjectionValuesTest, \
-    FieldValuesTest, \
-    create_obj
-from yt.utilities.on_demand_imports import _f90nml as f90nml
-from yt.frontends.ramses.api import RAMSESDataset
-from yt.config import ytcfg
-from yt.frontends.ramses.field_handlers import DETECTED_FIELDS, HydroFieldFileHandler
 import os
-import yt
+
 import numpy as np
 
+import yt
+from yt.config import ytcfg
+from yt.frontends.ramses.api import RAMSESDataset
+from yt.frontends.ramses.field_handlers import DETECTED_FIELDS, HydroFieldFileHandler
+from yt.testing import (
+    assert_equal,
+    requires_file,
+    requires_module,
+    units_override_check,
+)
+from yt.utilities.answer_testing.framework import (
+    FieldValuesTest,
+    PixelizedProjectionValuesTest,
+    create_obj,
+    data_dir_load,
+    requires_ds,
+)
+from yt.utilities.on_demand_imports import _f90nml as f90nml
+
 _fields = ("temperature", "density", "velocity_magnitude")
 
 output_00080 = "output_00080/info_00080.txt"
diff --git a/yt/frontends/rockstar/__init__.py b/yt/frontends/rockstar/__init__.py
index ff6a8d86064..c1b25fc798f 100644
--- a/yt/frontends/rockstar/__init__.py
+++ b/yt/frontends/rockstar/__init__.py
@@ -5,4 +5,3 @@
 
 
 """
-
diff --git a/yt/frontends/rockstar/api.py b/yt/frontends/rockstar/api.py
index f5bf766246d..94204007e97 100644
--- a/yt/frontends/rockstar/api.py
+++ b/yt/frontends/rockstar/api.py
@@ -1,10 +1,4 @@
-from .data_structures import \
-     RockstarDataset
-
-from .io import \
-     IOHandlerRockstarBinary
-
-from .fields import \
-     RockstarFieldInfo
-
 from . import tests
+from .data_structures import RockstarDataset
+from .fields import RockstarFieldInfo
+from .io import IOHandlerRockstarBinary
diff --git a/yt/frontends/rockstar/data_structures.py b/yt/frontends/rockstar/data_structures.py
index 7daa1231178..a57ba578aa2 100644
--- a/yt/frontends/rockstar/data_structures.py
+++ b/yt/frontends/rockstar/data_structures.py
@@ -1,23 +1,18 @@
-import numpy as np
 import glob
 import os
 
-from .fields import \
-    RockstarFieldInfo
-
-from yt.data_objects.static_output import \
-    ParticleDataset
-from yt.frontends.halo_catalog.data_structures import \
-    HaloCatalogFile
-from yt.funcs import \
-    setdefaultattr
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
-from yt.utilities.cosmology import Cosmology
+import numpy as np
+
 import yt.utilities.fortran_utils as fpu
+from yt.data_objects.static_output import ParticleDataset
+from yt.frontends.halo_catalog.data_structures import HaloCatalogFile
+from yt.funcs import setdefaultattr
+from yt.geometry.particle_geometry_handler import ParticleIndex
+from yt.utilities.cosmology import Cosmology
+
+from .definitions import header_dt
+from .fields import RockstarFieldInfo
 
-from .definitions import \
-    header_dt
 
 class RockstarBinaryFile(HaloCatalogFile):
     def __init__(self, ds, io, filename, file_id, range):
diff --git a/yt/frontends/rockstar/fields.py b/yt/frontends/rockstar/fields.py
index 5f5eb074c14..3b7483af842 100644
--- a/yt/frontends/rockstar/fields.py
+++ b/yt/frontends/rockstar/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 m_units = "Msun / h"                # Msun / h
 p_units = "Mpccm / h"               # Mpc / h comoving
diff --git a/yt/frontends/rockstar/io.py b/yt/frontends/rockstar/io.py
index a8a4c14d2b4..fb49bc77cf3 100644
--- a/yt/frontends/rockstar/io.py
+++ b/yt/frontends/rockstar/io.py
@@ -1,16 +1,14 @@
-import numpy as np
 import os
 
-from yt.funcs import mylog
-
-from yt.utilities.exceptions import \
-    YTDomainOverflow
+import numpy as np
 
-from yt.utilities.io_handler import \
-    BaseIOHandler
+from yt.funcs import mylog
+from yt.utilities.exceptions import YTDomainOverflow
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.lib.geometry_utils import compute_morton
 
 from .definitions import halo_dts
-from yt.utilities.lib.geometry_utils import compute_morton
+
 
 class IOHandlerRockstarBinary(BaseIOHandler):
     _dataset_type = "rockstar_binary"
diff --git a/yt/frontends/rockstar/tests/test_outputs.py b/yt/frontends/rockstar/tests/test_outputs.py
index e73f08d9e64..ca0cbbbe913 100644
--- a/yt/frontends/rockstar/tests/test_outputs.py
+++ b/yt/frontends/rockstar/tests/test_outputs.py
@@ -1,13 +1,12 @@
 import os.path
-from yt.testing import \
-    assert_equal, \
-    requires_file, \
-    ParticleSelectionComparison
-from yt.utilities.answer_testing.framework import \
-    FieldValuesTest, \
-    requires_ds, \
-    data_dir_load
+
 from yt.frontends.rockstar.api import RockstarDataset
+from yt.testing import ParticleSelectionComparison, assert_equal, requires_file
+from yt.utilities.answer_testing.framework import (
+    FieldValuesTest,
+    data_dir_load,
+    requires_ds,
+)
 
 _fields = ("particle_position_x", "particle_position_y",
            "particle_position_z", "particle_mass")
diff --git a/yt/frontends/sdf/__init__.py b/yt/frontends/sdf/__init__.py
index 0b0b7c6914e..ccdc42900c5 100644
--- a/yt/frontends/sdf/__init__.py
+++ b/yt/frontends/sdf/__init__.py
@@ -5,4 +5,3 @@
 
 
 """
-
diff --git a/yt/frontends/sdf/api.py b/yt/frontends/sdf/api.py
index cb431dd2289..a072588e740 100644
--- a/yt/frontends/sdf/api.py
+++ b/yt/frontends/sdf/api.py
@@ -1,8 +1,3 @@
-from .data_structures import \
-      SDFDataset
-
-from .io import \
-      IOHandlerSDF
-
-from .fields import \
-      SDFFieldInfo
+from .data_structures import SDFDataset
+from .fields import SDFFieldInfo
+from .io import IOHandlerSDF
diff --git a/yt/frontends/sdf/data_structures.py b/yt/frontends/sdf/data_structures.py
index 50ee7dc9daa..fa7a16f7fe9 100644
--- a/yt/frontends/sdf/data_structures.py
+++ b/yt/frontends/sdf/data_structures.py
@@ -1,24 +1,18 @@
 
-import numpy as np
+import contextlib
 import os
 import sys
-import contextlib
 
+import numpy as np
+
+from yt.data_objects.static_output import ParticleDataset, ParticleFile
+from yt.funcs import get_requests, setdefaultattr
+from yt.geometry.particle_geometry_handler import ParticleIndex
 from yt.utilities.logger import ytLogger as mylog
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
-from yt.data_objects.static_output import \
-    ParticleDataset, \
-    ParticleFile
-from yt.funcs import \
-    get_requests, \
-    setdefaultattr
-from .fields import \
-    SDFFieldInfo
-from yt.utilities.sdf import \
-    SDFRead,\
-    SDFIndex,\
-    HTTPSDFRead
+from yt.utilities.sdf import HTTPSDFRead, SDFIndex, SDFRead
+
+from .fields import SDFFieldInfo
+
 
 @contextlib.contextmanager
 def safeopen(*args, **kwargs):
diff --git a/yt/frontends/sdf/fields.py b/yt/frontends/sdf/fields.py
index 2abd0fbe167..bd72c2d0c73 100644
--- a/yt/frontends/sdf/fields.py
+++ b/yt/frontends/sdf/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 
 class SDFFieldInfo(FieldInfoContainer):
@@ -39,5 +38,3 @@ def __init__(self, ds, field_list):
             (mnf, ('code_mass', ['particle_mass'], None)),
         )
         super(SDFFieldInfo, self).__init__(ds, field_list)
-
-
diff --git a/yt/frontends/sdf/io.py b/yt/frontends/sdf/io.py
index b1944b3a425..8bbd32c9278 100644
--- a/yt/frontends/sdf/io.py
+++ b/yt/frontends/sdf/io.py
@@ -1,10 +1,8 @@
 import numpy as np
 
-from yt.utilities.io_handler import \
-    BaseIOHandler
-
 from yt.funcs import mylog
 from yt.utilities.exceptions import YTDomainOverflow
+from yt.utilities.io_handler import BaseIOHandler
 from yt.utilities.lib.geometry_utils import compute_morton
 
 CHUNKSIZE = 32**3
@@ -243,4 +241,3 @@ def _identify_fields(self, data_file):
 
 class IOHandlerSIndexHTTPSDF(IOHandlerSIndexSDF):
     _dataset_type = "midx_http_sdf_particles"
-
diff --git a/yt/frontends/sdf/tests/test_outputs.py b/yt/frontends/sdf/tests/test_outputs.py
index 24f0497ef69..7b0e1507826 100644
--- a/yt/frontends/sdf/tests/test_outputs.py
+++ b/yt/frontends/sdf/tests/test_outputs.py
@@ -1,11 +1,11 @@
-import numpy as np
 import socket
 import urllib
-from yt.testing import assert_equal
+
+import numpy as np
+
 from yt.frontends.sdf.api import SDFDataset
+from yt.testing import assert_equal, requires_module
 from yt.visualization.api import ProjectionPlot
-from yt.testing import requires_module
-
 
 _fields = (('deposit', 'all_cic'))
 slac_scivis_data = "http://darksky.slac.stanford.edu/scivis2015/data/ds14_scivis_0128/ds14_scivis_0128_e4_dt04_1.0000"
diff --git a/yt/frontends/sph/__init__.py b/yt/frontends/sph/__init__.py
index 377e37fa8ab..a31bfb84985 100644
--- a/yt/frontends/sph/__init__.py
+++ b/yt/frontends/sph/__init__.py
@@ -5,4 +5,3 @@
 
 
 """
-
diff --git a/yt/frontends/sph/api.py b/yt/frontends/sph/api.py
index 8177a1f3f08..d82a2cdab29 100644
--- a/yt/frontends/sph/api.py
+++ b/yt/frontends/sph/api.py
@@ -5,4 +5,3 @@
 
 
 """
-
diff --git a/yt/frontends/sph/data_structures.py b/yt/frontends/sph/data_structures.py
index b2d420b43a2..45df2fc2a1d 100644
--- a/yt/frontends/sph/data_structures.py
+++ b/yt/frontends/sph/data_structures.py
@@ -1,12 +1,11 @@
-import numpy as np
 import os
 
-from yt.data_objects.static_output import \
-    ParticleDataset
-from yt.funcs import \
-    mylog
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
+import numpy as np
+
+from yt.data_objects.static_output import ParticleDataset
+from yt.funcs import mylog
+from yt.geometry.particle_geometry_handler import ParticleIndex
+
 
 class SPHDataset(ParticleDataset):
     default_kernel_name = "cubic"
diff --git a/yt/frontends/sph/fields.py b/yt/frontends/sph/fields.py
index 3bbeb7a3c36..eb8d97defd3 100644
--- a/yt/frontends/sph/fields.py
+++ b/yt/frontends/sph/fields.py
@@ -1,7 +1,6 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
-from yt.fields.species_fields import \
-    setup_species_fields
+from yt.fields.field_info_container import FieldInfoContainer
+from yt.fields.species_fields import setup_species_fields
+
 
 class SPHFieldInfo(FieldInfoContainer):
     known_other_fields = ()
diff --git a/yt/frontends/sph/io.py b/yt/frontends/sph/io.py
index 644dbafb9e3..cc16536bfaa 100644
--- a/yt/frontends/sph/io.py
+++ b/yt/frontends/sph/io.py
@@ -5,8 +5,8 @@
 
 
 """
-from yt.utilities.io_handler import \
-    BaseIOHandler
+from yt.utilities.io_handler import BaseIOHandler
+
 
 class IOHandlerSPH(BaseIOHandler):
     """IOHandler implementation specifically for SPH data
diff --git a/yt/frontends/stream/api.py b/yt/frontends/stream/api.py
index 5b751ee8bc1..c4441a726f8 100644
--- a/yt/frontends/stream/api.py
+++ b/yt/frontends/stream/api.py
@@ -1,23 +1,17 @@
-from .data_structures import \
-      StreamGrid, \
-      StreamHierarchy, \
-      StreamDataset, \
-      StreamHandler, \
-      load_uniform_grid, \
-      load_amr_grids, \
-      load_particles, \
-      load_hexahedral_mesh, \
-      hexahedral_connectivity, \
-      load_octree, \
-      refine_amr, \
-      load_unstructured_mesh
-
-from .fields import \
-      StreamFieldInfo
-
-from .io import \
-      IOHandlerStream
-
-from . import tests
-
-from . import sample_data
+from . import sample_data, tests
+from .data_structures import (
+    StreamDataset,
+    StreamGrid,
+    StreamHandler,
+    StreamHierarchy,
+    hexahedral_connectivity,
+    load_amr_grids,
+    load_hexahedral_mesh,
+    load_octree,
+    load_particles,
+    load_uniform_grid,
+    load_unstructured_mesh,
+    refine_amr,
+)
+from .fields import StreamFieldInfo
+from .io import IOHandlerStream
diff --git a/yt/frontends/stream/data_structures.py b/yt/frontends/stream/data_structures.py
index 5ff99498595..444b8c99e22 100644
--- a/yt/frontends/stream/data_structures.py
+++ b/yt/frontends/stream/data_structures.py
@@ -1,75 +1,48 @@
 import os
 import time
-import weakref
-import numpy as np
 import uuid
-from itertools import \
-    chain, \
-    product, \
-    repeat
+import weakref
 from collections import defaultdict
-
+from itertools import chain, product, repeat
 from numbers import Number as numeric_type
 
-from yt.utilities.lib.cykdtree import PyKDTree
-from yt.funcs import \
-    iterable, \
-    ensure_list, \
-    issue_deprecation_warning
+import numpy as np
+
+from yt.data_objects.field_data import YTFieldData
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.octree_subset import OctreeSubset
+from yt.data_objects.particle_unions import ParticleUnion
+from yt.data_objects.static_output import Dataset, ParticleFile
+from yt.data_objects.unions import MeshUnion
+from yt.data_objects.unstructured_mesh import SemiStructuredMesh, UnstructuredMesh
+from yt.frontends.exodus_ii.util import get_num_pseudo_dims
+from yt.frontends.sph.data_structures import SPHParticleIndex
+from yt.funcs import ensure_list, issue_deprecation_warning, iterable
+from yt.geometry.geometry_handler import YTDataChunk
+from yt.geometry.grid_container import GridTree, MatchPointsToGrids
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.geometry.oct_container import OctreeContainer
+from yt.geometry.oct_geometry_handler import OctreeIndex
+from yt.geometry.unstructured_mesh_handler import UnstructuredIndex
+from yt.units.yt_array import YTQuantity, uconcatenate
+from yt.utilities.decompose import decompose_array, get_psize
+from yt.utilities.exceptions import (
+    YTIllDefinedAMR,
+    YTInconsistentGridFieldShape,
+    YTInconsistentGridFieldShapeGridDims,
+    YTInconsistentParticleFieldShape,
+)
+from yt.utilities.flagging_methods import FlaggingGrid
 from yt.utilities.io_handler import io_registry
-from yt.data_objects.field_data import \
-    YTFieldData
-from yt.data_objects.particle_unions import \
-    ParticleUnion
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.data_objects.static_output import \
-    ParticleFile
-from yt.frontends.sph.data_structures import \
-    SPHParticleIndex
-from yt.geometry.geometry_handler import \
-    YTDataChunk
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.data_objects.octree_subset import \
-    OctreeSubset
-from yt.geometry.oct_geometry_handler import \
-    OctreeIndex
-from yt.geometry.oct_container import \
-    OctreeContainer
-from yt.geometry.unstructured_mesh_handler import \
-    UnstructuredIndex
-from yt.data_objects.static_output import \
-    Dataset
+from yt.utilities.lib.cykdtree import PyKDTree
+from yt.utilities.lib.misc_utilities import get_box_grids_level
+from yt.utilities.lib.particle_kdtree_tools import (
+    estimate_density,
+    generate_smoothing_length,
+)
 from yt.utilities.logger import ytLogger as mylog
-from yt.utilities.lib.misc_utilities import \
-    get_box_grids_level
-from yt.utilities.lib.particle_kdtree_tools import \
-    generate_smoothing_length, \
-    estimate_density
-from yt.geometry.grid_container import \
-    GridTree, \
-    MatchPointsToGrids
-from yt.utilities.decompose import \
-    decompose_array, get_psize
-from yt.utilities.exceptions import \
-    YTIllDefinedAMR, \
-    YTInconsistentGridFieldShape, \
-    YTInconsistentParticleFieldShape, \
-    YTInconsistentGridFieldShapeGridDims
-from yt.units.yt_array import \
-    YTQuantity, \
-    uconcatenate
-from yt.utilities.flagging_methods import \
-    FlaggingGrid
-from yt.data_objects.unstructured_mesh import \
-    SemiStructuredMesh, \
-    UnstructuredMesh
-from .fields import \
-    StreamFieldInfo
-from yt.frontends.exodus_ii.util import \
-    get_num_pseudo_dims
-from yt.data_objects.unions import MeshUnion
+
+from .fields import StreamFieldInfo
 
 
 class StreamGrid(AMRGridPatch):
diff --git a/yt/frontends/stream/fields.py b/yt/frontends/stream/fields.py
index 8c43a8027e1..cffeb150352 100644
--- a/yt/frontends/stream/fields.py
+++ b/yt/frontends/stream/fields.py
@@ -1,5 +1,4 @@
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 
 class StreamFieldInfo(FieldInfoContainer):
diff --git a/yt/frontends/stream/io.py b/yt/frontends/stream/io.py
index 70717a4d142..0f5b72c45e6 100644
--- a/yt/frontends/stream/io.py
+++ b/yt/frontends/stream/io.py
@@ -1,9 +1,9 @@
 import numpy as np
 
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.utilities.logger import ytLogger as mylog
 from yt.utilities.exceptions import YTDomainOverflow
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.logger import ytLogger as mylog
+
 
 class IOHandlerStream(BaseIOHandler):
 
@@ -286,4 +286,3 @@ def _read_fluid_selection(self, chunks, selector, fields, size):
                 ind += g.select(selector, ds, rv[field], ind) # caches
             rv[field] = rv[field][:ind]
         return rv
-
diff --git a/yt/frontends/stream/tests/test_outputs.py b/yt/frontends/stream/tests/test_outputs.py
index a3c561aaceb..3b3e1fdad1b 100644
--- a/yt/frontends/stream/tests/test_outputs.py
+++ b/yt/frontends/stream/tests/test_outputs.py
@@ -1,20 +1,20 @@
-import numpy as np
 import os
 import shutil
 import tempfile
 import unittest
 
-from yt.frontends.stream.data_structures import load_uniform_grid, \
-    load_particles
-from yt.testing import \
-    assert_equal, \
-    assert_raises
+import numpy as np
+
 from yt.convenience import load
-from yt.utilities.exceptions import \
-    YTOutputNotIdentified, \
-    YTInconsistentGridFieldShape, \
-    YTInconsistentParticleFieldShape, \
-    YTInconsistentGridFieldShapeGridDims
+from yt.frontends.stream.data_structures import load_particles, load_uniform_grid
+from yt.testing import assert_equal, assert_raises
+from yt.utilities.exceptions import (
+    YTInconsistentGridFieldShape,
+    YTInconsistentGridFieldShapeGridDims,
+    YTInconsistentParticleFieldShape,
+    YTOutputNotIdentified,
+)
+
 
 class TestEmptyLoad(unittest.TestCase):
 
diff --git a/yt/frontends/stream/tests/test_stream_amrgrids.py b/yt/frontends/stream/tests/test_stream_amrgrids.py
index 798a02b41dc..ff8d3a84bbd 100644
--- a/yt/frontends/stream/tests/test_stream_amrgrids.py
+++ b/yt/frontends/stream/tests/test_stream_amrgrids.py
@@ -1,11 +1,9 @@
 import numpy as np
-from yt.utilities.exceptions import \
-    YTIllDefinedAMR, \
-    YTIntDomainOverflow
-
-from yt import load_amr_grids, ProjectionPlot
 
+from yt import ProjectionPlot, load_amr_grids
 from yt.testing import assert_raises
+from yt.utilities.exceptions import YTIllDefinedAMR, YTIntDomainOverflow
+
 
 def test_qt_overflow():
     grid_data = []
diff --git a/yt/frontends/stream/tests/test_stream_hexahedral.py b/yt/frontends/stream/tests/test_stream_hexahedral.py
index 4816139a730..1365dd68f21 100644
--- a/yt/frontends/stream/tests/test_stream_hexahedral.py
+++ b/yt/frontends/stream/tests/test_stream_hexahedral.py
@@ -1,12 +1,10 @@
 import numpy as np
-from yt.frontends.stream.api import \
-    load_hexahedral_mesh
-from yt.frontends.stream.data_structures import \
-    hexahedral_connectivity
-from yt.testing import \
-    assert_almost_equal, \
-    assert_equal
+
 from yt import SlicePlot
+from yt.frontends.stream.api import load_hexahedral_mesh
+from yt.frontends.stream.data_structures import hexahedral_connectivity
+from yt.testing import assert_almost_equal, assert_equal
+
 # Field information
 
 def test_stream_hexahedral() :
diff --git a/yt/frontends/stream/tests/test_stream_octree.py b/yt/frontends/stream/tests/test_stream_octree.py
index 0f88a1821dc..a4cbd2a4056 100644
--- a/yt/frontends/stream/tests/test_stream_octree.py
+++ b/yt/frontends/stream/tests/test_stream_octree.py
@@ -1,6 +1,7 @@
-import yt
 import numpy as np
 
+import yt
+
 OCT_MASK_LIST = [8, 0, 0, 0, 0, 8, 0, 0,
                  0, 0, 0, 0, 0, 0, 0, 0,
                  8, 0, 0, 0, 0, 0, 0, 0,
diff --git a/yt/frontends/stream/tests/test_stream_particles.py b/yt/frontends/stream/tests/test_stream_particles.py
index cfc5336eebe..8bb4c874df5 100644
--- a/yt/frontends/stream/tests/test_stream_particles.py
+++ b/yt/frontends/stream/tests/test_stream_particles.py
@@ -1,15 +1,14 @@
 import numpy as np
 
-from yt.testing import \
-    assert_equal, \
-    fake_particle_ds, \
-    fake_sph_orientation_ds
-from yt.frontends.stream.api import load_uniform_grid, \
-    refine_amr, \
-    load_amr_grids, \
-    load_particles
-import yt.utilities.initial_conditions as ic
 import yt.utilities.flagging_methods as fm
+import yt.utilities.initial_conditions as ic
+from yt.frontends.stream.api import (
+    load_amr_grids,
+    load_particles,
+    load_uniform_grid,
+    refine_amr,
+)
+from yt.testing import assert_equal, fake_particle_ds, fake_sph_orientation_ds
 
 # Field information
 
diff --git a/yt/frontends/stream/tests/test_stream_unstructured.py b/yt/frontends/stream/tests/test_stream_unstructured.py
index 5feecedc60c..8e3bee46dc2 100644
--- a/yt/frontends/stream/tests/test_stream_unstructured.py
+++ b/yt/frontends/stream/tests/test_stream_unstructured.py
@@ -1,6 +1,7 @@
 import numpy as np
 
-from yt import load_unstructured_mesh, SlicePlot
+from yt import SlicePlot, load_unstructured_mesh
+
 
 def test_multi_mesh():
     coordsMulti = np.array([[0.0, 0.0],
diff --git a/yt/frontends/stream/tests/test_update_data.py b/yt/frontends/stream/tests/test_update_data.py
index 195031ab9f4..eb58a440a9c 100644
--- a/yt/frontends/stream/tests/test_update_data.py
+++ b/yt/frontends/stream/tests/test_update_data.py
@@ -1,8 +1,8 @@
 import numpy as np
-from yt.testing import \
-    fake_particle_ds, \
-    fake_random_ds
+
 from yt.data_objects.profiles import create_profile
+from yt.testing import fake_particle_ds, fake_random_ds
+
 
 def test_update_data_grid():
     ds = fake_random_ds(64, nprocs=8)
diff --git a/yt/frontends/swift/api.py b/yt/frontends/swift/api.py
index 960d56cdf62..607c3e6787d 100644
--- a/yt/frontends/swift/api.py
+++ b/yt/frontends/swift/api.py
@@ -1,10 +1,5 @@
-from .data_structures import \
-    SwiftDataset
-
-from yt.frontends.sph.fields import \
-    SPHFieldInfo
-
-from .io import \
-    IOHandlerSwift
+from yt.frontends.sph.fields import SPHFieldInfo
 
 from . import tests
+from .data_structures import SwiftDataset
+from .io import IOHandlerSwift
diff --git a/yt/frontends/swift/data_structures.py b/yt/frontends/swift/data_structures.py
index d56360dc157..47917407d59 100644
--- a/yt/frontends/swift/data_structures.py
+++ b/yt/frontends/swift/data_structures.py
@@ -1,15 +1,14 @@
-import numpy as np
-from yt.utilities.on_demand_imports import _h5py as h5py
 from uuid import uuid4
 
-from yt.utilities.logger import ytLogger as mylog
-from yt.frontends.sph.data_structures import \
-    SPHDataset, \
-    SPHParticleIndex
+import numpy as np
+
+from yt.data_objects.static_output import ParticleFile
+from yt.frontends.sph.data_structures import SPHDataset, SPHParticleIndex
 from yt.frontends.sph.fields import SPHFieldInfo
-from yt.data_objects.static_output import \
-    ParticleFile
 from yt.funcs import only_on_root
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.on_demand_imports import _h5py as h5py
+
 
 class SwiftDataset(SPHDataset):
     _index_class = SPHParticleIndex
diff --git a/yt/frontends/swift/io.py b/yt/frontends/swift/io.py
index 54a529d85d6..401f84b07e2 100644
--- a/yt/frontends/swift/io.py
+++ b/yt/frontends/swift/io.py
@@ -1,8 +1,8 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
 import numpy as np
 
-from yt.frontends.sph.io import \
-    IOHandlerSPH
+from yt.frontends.sph.io import IOHandlerSPH
+from yt.utilities.on_demand_imports import _h5py as h5py
+
 
 class IOHandlerSwift(IOHandlerSPH):
     _dataset_type = "swift"
diff --git a/yt/frontends/swift/tests/test_outputs.py b/yt/frontends/swift/tests/test_outputs.py
index a358e97b411..e0a8846a009 100644
--- a/yt/frontends/swift/tests/test_outputs.py
+++ b/yt/frontends/swift/tests/test_outputs.py
@@ -1,10 +1,8 @@
-from yt import load
-
 import numpy as np
 
-from yt.testing import requires_file
+from yt import load
 from yt.frontends.swift.api import SwiftDataset
-from yt.testing import assert_almost_equal, ParticleSelectionComparison
+from yt.testing import ParticleSelectionComparison, assert_almost_equal, requires_file
 from yt.utilities.on_demand_imports import _h5py as h5py
 
 keplerian_ring = "KeplerianRing/keplerian_ring_0020.hdf5"
diff --git a/yt/frontends/tipsy/api.py b/yt/frontends/tipsy/api.py
index a0fd0ad2986..58fe586cf18 100644
--- a/yt/frontends/tipsy/api.py
+++ b/yt/frontends/tipsy/api.py
@@ -1,10 +1,4 @@
-from .data_structures import \
-    TipsyDataset
-
-from .fields import \
-    TipsyFieldInfo
-    
-from .io import \
-    IOHandlerTipsyBinary
-     
 from . import tests
+from .data_structures import TipsyDataset
+from .fields import TipsyFieldInfo
+from .io import IOHandlerTipsyBinary
diff --git a/yt/frontends/tipsy/data_structures.py b/yt/frontends/tipsy/data_structures.py
index fac6addd0b7..77d3e9c757c 100644
--- a/yt/frontends/tipsy/data_structures.py
+++ b/yt/frontends/tipsy/data_structures.py
@@ -1,25 +1,19 @@
-import numpy as np
-import struct
 import glob
 import os
+import struct
+import sys
 
-from yt.frontends.sph.data_structures import \
-    SPHDataset, \
-    SPHParticleIndex
+import numpy as np
+
+from yt.data_objects.static_output import ParticleFile
+from yt.frontends.sph.data_structures import SPHDataset, SPHParticleIndex
 from yt.funcs import deprecate
-from yt.data_objects.static_output import \
-    ParticleFile
-from yt.utilities.cosmology import \
-    Cosmology
-from yt.utilities.physical_constants import \
-    G
-from yt.utilities.physical_ratios import \
-    cm_per_kpc
-
-from .fields import \
-    TipsyFieldInfo
+from yt.utilities.cosmology import Cosmology
+from yt.utilities.physical_constants import G
+from yt.utilities.physical_ratios import cm_per_kpc
+
+from .fields import TipsyFieldInfo
 
-import sys
 if sys.version_info > (3,):
     long = int
 
diff --git a/yt/frontends/tipsy/fields.py b/yt/frontends/tipsy/fields.py
index 2cfd0c04a20..35aa54ac6b9 100644
--- a/yt/frontends/tipsy/fields.py
+++ b/yt/frontends/tipsy/fields.py
@@ -1,5 +1,6 @@
 from yt.frontends.sph.fields import SPHFieldInfo
 
+
 class TipsyFieldInfo(SPHFieldInfo):
     known_particle_fields = SPHFieldInfo.known_particle_fields + \
         (("smoothing_length", ("code_length", [], None)),)
diff --git a/yt/frontends/tipsy/io.py b/yt/frontends/tipsy/io.py
index 11dcceffce8..dce5d2f1c77 100644
--- a/yt/frontends/tipsy/io.py
+++ b/yt/frontends/tipsy/io.py
@@ -1,19 +1,15 @@
 import glob
-import numpy as np
-from numpy.lib.recfunctions import append_fields
 import os
 import struct
 
-from yt.geometry.particle_geometry_handler import \
-    CHUNKSIZE
-from yt.frontends.sph.io import \
-    IOHandlerSPH
-from yt.frontends.tipsy.definitions import \
-    npart_mapping
-from yt.utilities.lib.particle_kdtree_tools import \
-    generate_smoothing_length
-from yt.utilities.logger import ytLogger as \
-    mylog
+import numpy as np
+from numpy.lib.recfunctions import append_fields
+
+from yt.frontends.sph.io import IOHandlerSPH
+from yt.frontends.tipsy.definitions import npart_mapping
+from yt.geometry.particle_geometry_handler import CHUNKSIZE
+from yt.utilities.lib.particle_kdtree_tools import generate_smoothing_length
+from yt.utilities.logger import ytLogger as mylog
 
 
 class IOHandlerTipsyBinary(IOHandlerSPH):
diff --git a/yt/frontends/tipsy/tests/test_outputs.py b/yt/frontends/tipsy/tests/test_outputs.py
index 146615c8cd0..0a7979c5624 100644
--- a/yt/frontends/tipsy/tests/test_outputs.py
+++ b/yt/frontends/tipsy/tests/test_outputs.py
@@ -1,14 +1,13 @@
 from collections import OrderedDict
 
-from yt.testing import \
-    requires_file, \
-    ParticleSelectionComparison
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load, \
-    sph_answer, \
-    nbody_answer
 from yt.frontends.tipsy.api import TipsyDataset
+from yt.testing import ParticleSelectionComparison, requires_file
+from yt.utilities.answer_testing.framework import (
+    data_dir_load,
+    nbody_answer,
+    requires_ds,
+    sph_answer,
+)
 
 _fields = OrderedDict(
     [
diff --git a/yt/frontends/ytdata/__init__.py b/yt/frontends/ytdata/__init__.py
index 7cccc849a5c..5189c98ee97 100644
--- a/yt/frontends/ytdata/__init__.py
+++ b/yt/frontends/ytdata/__init__.py
@@ -5,4 +5,3 @@
 
 
 """
-
diff --git a/yt/frontends/ytdata/api.py b/yt/frontends/ytdata/api.py
index a7fdf936854..28fdb04a96d 100644
--- a/yt/frontends/ytdata/api.py
+++ b/yt/frontends/ytdata/api.py
@@ -1,27 +1,22 @@
-from .data_structures import \
-    YTDataContainerDataset, \
-    YTSpatialPlotDataset, \
-    YTGridDataset, \
-    YTGridHierarchy, \
-    YTGrid, \
-    YTNonspatialDataset, \
-    YTNonspatialHierarchy, \
-    YTNonspatialGrid, \
-    YTProfileDataset, \
-    YTClumpContainer, \
-    YTClumpTreeDataset
-
-from .io import \
-    IOHandlerYTDataContainerHDF5, \
-    IOHandlerYTGridHDF5, \
-    IOHandlerYTSpatialPlotHDF5, \
-    IOHandlerYTNonspatialhdf5
-
-from .fields import \
-    YTDataContainerFieldInfo, \
-    YTGridFieldInfo
-
-from .utilities import \
-    save_as_dataset
-
 from . import tests
+from .data_structures import (
+    YTClumpContainer,
+    YTClumpTreeDataset,
+    YTDataContainerDataset,
+    YTGrid,
+    YTGridDataset,
+    YTGridHierarchy,
+    YTNonspatialDataset,
+    YTNonspatialGrid,
+    YTNonspatialHierarchy,
+    YTProfileDataset,
+    YTSpatialPlotDataset,
+)
+from .fields import YTDataContainerFieldInfo, YTGridFieldInfo
+from .io import (
+    IOHandlerYTDataContainerHDF5,
+    IOHandlerYTGridHDF5,
+    IOHandlerYTNonspatialhdf5,
+    IOHandlerYTSpatialPlotHDF5,
+)
+from .utilities import save_as_dataset
diff --git a/yt/frontends/ytdata/data_structures.py b/yt/frontends/ytdata/data_structures.py
index 88b91f4f0cc..f4785ecdd24 100644
--- a/yt/frontends/ytdata/data_structures.py
+++ b/yt/frontends/ytdata/data_structures.py
@@ -1,55 +1,33 @@
-from collections import \
-    defaultdict
-from numbers import \
-    Number as numeric_type
-import numpy as np
 import os
 import weakref
+from collections import defaultdict
+from numbers import Number as numeric_type
+
+import numpy as np
 
-from .fields import \
-    YTDataContainerFieldInfo, \
-    YTGridFieldInfo
-
-from yt.data_objects.grid_patch import \
-    AMRGridPatch
-from yt.data_objects.particle_unions import \
-    ParticleUnion
-from yt.data_objects.profiles import \
-    Profile1DFromDataset, \
-    Profile2DFromDataset, \
-    Profile3DFromDataset
-from yt.data_objects.static_output import \
-    Dataset, \
-    ParticleFile, \
-    validate_index_order
-from yt.funcs import \
-    is_root, \
-    parse_h5_attr
-from yt.geometry.grid_geometry_handler import \
-    GridIndex
-from yt.geometry.particle_geometry_handler import \
-    ParticleIndex
-from yt.units import \
-    dimensions
-from yt.units.unit_registry import \
-    UnitRegistry
-from yt.units.yt_array import \
-    uconcatenate, \
-    YTQuantity
-from yt.utilities.logger import \
-    ytLogger as mylog
-from yt.utilities.exceptions import \
-    YTFieldTypeNotFound
-from yt.utilities.on_demand_imports import \
-    _h5py as h5py
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_root_only
-from yt.utilities.tree_container import \
-    TreeContainer
-from yt.fields.field_exceptions import \
-    NeedsGridType
-from yt.data_objects.data_containers import \
-    GenerationInProgress
+from yt.data_objects.data_containers import GenerationInProgress
+from yt.data_objects.grid_patch import AMRGridPatch
+from yt.data_objects.particle_unions import ParticleUnion
+from yt.data_objects.profiles import (
+    Profile1DFromDataset,
+    Profile2DFromDataset,
+    Profile3DFromDataset,
+)
+from yt.data_objects.static_output import Dataset, ParticleFile, validate_index_order
+from yt.fields.field_exceptions import NeedsGridType
+from yt.funcs import is_root, parse_h5_attr
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.geometry.particle_geometry_handler import ParticleIndex
+from yt.units import dimensions
+from yt.units.unit_registry import UnitRegistry
+from yt.units.yt_array import YTQuantity, uconcatenate
+from yt.utilities.exceptions import YTFieldTypeNotFound
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.on_demand_imports import _h5py as h5py
+from yt.utilities.parallel_tools.parallel_analysis_interface import parallel_root_only
+from yt.utilities.tree_container import TreeContainer
+
+from .fields import YTDataContainerFieldInfo, YTGridFieldInfo
 
 _grid_data_containers = ["arbitrary_grid",
                          "covering_grid",
diff --git a/yt/frontends/ytdata/fields.py b/yt/frontends/ytdata/fields.py
index 2ecb400e2ed..9d7116d3c43 100644
--- a/yt/frontends/ytdata/fields.py
+++ b/yt/frontends/ytdata/fields.py
@@ -1,6 +1,5 @@
 
-from yt.fields.field_info_container import \
-    FieldInfoContainer
+from yt.fields.field_info_container import FieldInfoContainer
 
 m_units = "g"
 p_units = "cm"
diff --git a/yt/frontends/ytdata/io.py b/yt/frontends/ytdata/io.py
index 2ad30b9ef3d..5c1076cc6f0 100644
--- a/yt/frontends/ytdata/io.py
+++ b/yt/frontends/ytdata/io.py
@@ -1,20 +1,13 @@
 import numpy as np
 
-from yt.funcs import \
-    mylog, \
-    parse_h5_attr
-from yt.geometry.selection_routines import \
-    GridSelector
-from yt.units.yt_array import \
-    uvstack
-from yt.utilities.exceptions import \
-    YTDomainOverflow
-from yt.utilities.io_handler import \
-    BaseIOHandler
-from yt.utilities.lib.geometry_utils import \
-    compute_morton
-from yt.utilities.on_demand_imports import \
-    _h5py as h5py
+from yt.funcs import mylog, parse_h5_attr
+from yt.geometry.selection_routines import GridSelector
+from yt.units.yt_array import uvstack
+from yt.utilities.exceptions import YTDomainOverflow
+from yt.utilities.io_handler import BaseIOHandler
+from yt.utilities.lib.geometry_utils import compute_morton
+from yt.utilities.on_demand_imports import _h5py as h5py
+
 
 class IOHandlerYTNonspatialhdf5(BaseIOHandler):
     _dataset_type = "ytnonspatialhdf5"
diff --git a/yt/frontends/ytdata/tests/test_old_outputs.py b/yt/frontends/ytdata/tests/test_old_outputs.py
index 60c384ffdb6..55ee895ea60 100644
--- a/yt/frontends/ytdata/tests/test_old_outputs.py
+++ b/yt/frontends/ytdata/tests/test_old_outputs.py
@@ -13,38 +13,35 @@
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
-from yt.data_objects.api import \
-    create_profile
-from yt.frontends.ytdata.api import \
-    YTDataContainerDataset, \
-    YTSpatialPlotDataset, \
-    YTGridDataset, \
-    YTNonspatialDataset, \
-    YTProfileDataset
-from yt.frontends.ytdata.tests.test_outputs import \
-    compare_unit_attributes, \
-    YTDataFieldTest
-from yt.testing import \
-    assert_allclose_units, \
-    assert_array_equal, \
-    assert_fname, \
-    requires_file, \
-    requires_module
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load
-from yt.units.yt_array import \
-    YTArray
-from yt.visualization.plot_window import \
-    SlicePlot, \
-    ProjectionPlot
-from yt.visualization.profile_plotter import \
-    ProfilePlot, \
-    PhasePlot
-import numpy as np
-import tempfile
 import os
 import shutil
+import tempfile
+
+import numpy as np
+
+from yt.data_objects.api import create_profile
+from yt.frontends.ytdata.api import (
+    YTDataContainerDataset,
+    YTGridDataset,
+    YTNonspatialDataset,
+    YTProfileDataset,
+    YTSpatialPlotDataset,
+)
+from yt.frontends.ytdata.tests.test_outputs import (
+    YTDataFieldTest,
+    compare_unit_attributes,
+)
+from yt.testing import (
+    assert_allclose_units,
+    assert_array_equal,
+    assert_fname,
+    requires_file,
+    requires_module,
+)
+from yt.units.yt_array import YTArray
+from yt.utilities.answer_testing.framework import data_dir_load, requires_ds
+from yt.visualization.plot_window import ProjectionPlot, SlicePlot
+from yt.visualization.profile_plotter import PhasePlot, ProfilePlot
 
 enzotiny = "enzo_tiny_cosmology/DD0046/DD0046"
 ytdata_dir = "ytdata_test"
diff --git a/yt/frontends/ytdata/tests/test_outputs.py b/yt/frontends/ytdata/tests/test_outputs.py
index 311720d1b4e..f536f542995 100644
--- a/yt/frontends/ytdata/tests/test_outputs.py
+++ b/yt/frontends/ytdata/tests/test_outputs.py
@@ -1,38 +1,36 @@
-from yt.convenience import \
-    load
-from yt.data_objects.api import \
-    create_profile
-from yt.frontends.ytdata.api import \
-    YTDataContainerDataset, \
-    YTSpatialPlotDataset, \
-    YTGridDataset, \
-    YTNonspatialDataset, \
-    YTProfileDataset, \
-    save_as_dataset
-from yt.testing import \
-    assert_array_equal, \
-    assert_allclose_units, \
-    assert_equal, \
-    assert_fname, \
-    fake_random_ds, \
-    requires_module
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load, \
-    AnswerTestingTest
-from yt.units.yt_array import \
-    YTArray, \
-    YTQuantity
-from yt.visualization.plot_window import \
-    SlicePlot, \
-    ProjectionPlot
-from yt.visualization.profile_plotter import \
-    ProfilePlot, \
-    PhasePlot
-import numpy as np
-import tempfile
 import os
 import shutil
+import tempfile
+
+import numpy as np
+
+from yt.convenience import load
+from yt.data_objects.api import create_profile
+from yt.frontends.ytdata.api import (
+    YTDataContainerDataset,
+    YTGridDataset,
+    YTNonspatialDataset,
+    YTProfileDataset,
+    YTSpatialPlotDataset,
+    save_as_dataset,
+)
+from yt.testing import (
+    assert_allclose_units,
+    assert_array_equal,
+    assert_equal,
+    assert_fname,
+    fake_random_ds,
+    requires_module,
+)
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.answer_testing.framework import (
+    AnswerTestingTest,
+    data_dir_load,
+    requires_ds,
+)
+from yt.visualization.plot_window import ProjectionPlot, SlicePlot
+from yt.visualization.profile_plotter import PhasePlot, ProfilePlot
+
 
 def make_tempdir():
     if int(os.environ.get('GENERATE_YTDATA', 0)):
diff --git a/yt/frontends/ytdata/utilities.py b/yt/frontends/ytdata/utilities.py
index c72e464ed70..e92a05fb07d 100644
--- a/yt/frontends/ytdata/utilities.py
+++ b/yt/frontends/ytdata/utilities.py
@@ -1,9 +1,7 @@
-from yt.units.yt_array import \
-    YTArray
-from yt.utilities.logger import \
-    ytLogger as mylog
-from yt.utilities.on_demand_imports import \
-    _h5py as h5py
+from yt.units.yt_array import YTArray
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.on_demand_imports import _h5py as h5py
+
 
 def save_as_dataset(ds, filename, data, field_types=None,
                     extra_attrs=None):
diff --git a/yt/funcs.py b/yt/funcs.py
index 31ecf4122a8..fa3a7c826d7 100644
--- a/yt/funcs.py
+++ b/yt/funcs.py
@@ -1,35 +1,35 @@
-import errno
+import base64
 import builtins
+import contextlib
 import copy
-import time
+import errno
+import getpass
+import glob
 import inspect
-import traceback
-import sys
-import pdb
+import itertools
 import os
+import pdb
 import re
-import contextlib
-import warnings
 import struct
 import subprocess
-import numpy as np
-import itertools
-import base64
-import numpy
-import matplotlib
-import getpass
-import glob
-from math import floor, ceil
+import sys
+import time
+import traceback
+import urllib.parse
+import urllib.request
+import warnings
+from functools import wraps
+from math import ceil, floor
 from numbers import Number as numeric_type
 
-import urllib.request
-import urllib.parse
-from yt.utilities.logger import ytLogger as mylog
-from yt.utilities.lru_cache import lru_cache
-from yt.utilities.exceptions import YTInvalidWidthError
+import matplotlib
+import numpy as np
+
 from yt.extern.tqdm import tqdm
 from yt.units import YTArray, YTQuantity
-from functools import wraps
+from yt.utilities.exceptions import YTInvalidWidthError
+from yt.utilities.logger import ytLogger as mylog
+from yt.utilities.lru_cache import lru_cache
 
 # Some functions for handling sequences and other types
 
diff --git a/yt/geometry/api.py b/yt/geometry/api.py
index 4adeee23510..4c001731bdf 100644
--- a/yt/geometry/api.py
+++ b/yt/geometry/api.py
@@ -1,5 +1,2 @@
-from .geometry_handler import \
-    Index
-
-from .grid_geometry_handler import \
-    GridIndex
+from .geometry_handler import Index
+from .grid_geometry_handler import GridIndex
diff --git a/yt/geometry/coordinates/api.py b/yt/geometry/coordinates/api.py
index 5a3c0f9c6b9..153c397dcf5 100644
--- a/yt/geometry/coordinates/api.py
+++ b/yt/geometry/coordinates/api.py
@@ -1,17 +1,10 @@
-from .coordinate_handler import \
-    CoordinateHandler
-
-from .cartesian_coordinates import \
-    CartesianCoordinateHandler
-from .polar_coordinates import \
-    PolarCoordinateHandler
-from .cylindrical_coordinates import \
-    CylindricalCoordinateHandler
-from .spherical_coordinates import \
-    SphericalCoordinateHandler
-from .geographic_coordinates import \
-     GeographicCoordinateHandler, \
-     InternalGeographicCoordinateHandler
-from .spec_cube_coordinates import \
-    SpectralCubeCoordinateHandler
-
+from .cartesian_coordinates import CartesianCoordinateHandler
+from .coordinate_handler import CoordinateHandler
+from .cylindrical_coordinates import CylindricalCoordinateHandler
+from .geographic_coordinates import (
+    GeographicCoordinateHandler,
+    InternalGeographicCoordinateHandler,
+)
+from .polar_coordinates import PolarCoordinateHandler
+from .spec_cube_coordinates import SpectralCubeCoordinateHandler
+from .spherical_coordinates import SphericalCoordinateHandler
diff --git a/yt/geometry/coordinates/cartesian_coordinates.py b/yt/geometry/coordinates/cartesian_coordinates.py
index 40e3364e780..eba9067bfb5 100644
--- a/yt/geometry/coordinates/cartesian_coordinates.py
+++ b/yt/geometry/coordinates/cartesian_coordinates.py
@@ -1,24 +1,28 @@
 import numpy as np
-from .coordinate_handler import \
-    CoordinateHandler, \
-    _get_coord_fields, \
-    _get_vert_fields, \
-    cartesian_to_cylindrical, \
-    cylindrical_to_cartesian
-from yt.funcs import mylog
-from yt.units.yt_array import uvstack, YTArray
-from yt.utilities.lib.pixelization_routines import \
-    pixelize_element_mesh, pixelize_off_axis_cartesian, \
-    pixelize_cartesian, \
-    pixelize_cartesian_nodal, \
-    pixelize_sph_kernel_slice, \
-    pixelize_sph_kernel_projection, \
-    pixelize_element_mesh_line, \
-    interpolate_sph_grid_gather, \
-    normalization_2d_utility
+
 from yt.data_objects.unstructured_mesh import SemiStructuredMesh
+from yt.funcs import mylog
+from yt.units.yt_array import YTArray, uconcatenate, uvstack
+from yt.utilities.lib.pixelization_routines import (
+    interpolate_sph_grid_gather,
+    normalization_2d_utility,
+    pixelize_cartesian,
+    pixelize_cartesian_nodal,
+    pixelize_element_mesh,
+    pixelize_element_mesh_line,
+    pixelize_off_axis_cartesian,
+    pixelize_sph_kernel_projection,
+    pixelize_sph_kernel_slice,
+)
 from yt.utilities.nodal_data_utils import get_nodal_data
-from yt.units.yt_array import uconcatenate
+
+from .coordinate_handler import (
+    CoordinateHandler,
+    _get_coord_fields,
+    _get_vert_fields,
+    cartesian_to_cylindrical,
+    cylindrical_to_cartesian,
+)
 
 
 def _sample_ray(ray, npoints, field):
diff --git a/yt/geometry/coordinates/coordinate_handler.py b/yt/geometry/coordinates/coordinate_handler.py
index d5521e804ac..0e9f2754b2c 100644
--- a/yt/geometry/coordinates/coordinate_handler.py
+++ b/yt/geometry/coordinates/coordinate_handler.py
@@ -1,16 +1,12 @@
-import numpy as np
 import weakref
 from numbers import Number
 
-from yt.funcs import \
-    validate_width_tuple, \
-    fix_unitary, \
-    iterable
-from yt.units.yt_array import \
-    YTArray, YTQuantity
-from yt.utilities.exceptions import \
-    YTCoordinateNotImplemented, \
-    YTInvalidWidthError
+import numpy as np
+
+from yt.funcs import fix_unitary, iterable, validate_width_tuple
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.exceptions import YTCoordinateNotImplemented, YTInvalidWidthError
+
 
 def _unknown_coord(field, data):
     raise YTCoordinateNotImplemented
diff --git a/yt/geometry/coordinates/cylindrical_coordinates.py b/yt/geometry/coordinates/cylindrical_coordinates.py
index ac5471fa07f..ed5adbd4402 100644
--- a/yt/geometry/coordinates/cylindrical_coordinates.py
+++ b/yt/geometry/coordinates/cylindrical_coordinates.py
@@ -1,12 +1,15 @@
 import numpy as np
-from .coordinate_handler import \
-    CoordinateHandler, \
-    _unknown_coord, \
-    _get_coord_fields, \
-    cylindrical_to_cartesian, \
-    cartesian_to_cylindrical
-from yt.utilities.lib.pixelization_routines import \
-    pixelize_cartesian, pixelize_cylinder
+
+from yt.utilities.lib.pixelization_routines import pixelize_cartesian, pixelize_cylinder
+
+from .coordinate_handler import (
+    CoordinateHandler,
+    _get_coord_fields,
+    _unknown_coord,
+    cartesian_to_cylindrical,
+    cylindrical_to_cartesian,
+)
+
 #
 # Cylindrical fields
 #
diff --git a/yt/geometry/coordinates/geographic_coordinates.py b/yt/geometry/coordinates/geographic_coordinates.py
index 0413d7d3ebe..60f2ea9eddf 100644
--- a/yt/geometry/coordinates/geographic_coordinates.py
+++ b/yt/geometry/coordinates/geographic_coordinates.py
@@ -1,10 +1,9 @@
 import numpy as np
-from .coordinate_handler import \
-    CoordinateHandler, \
-    _unknown_coord, \
-    _get_coord_fields
-from yt.utilities.lib.pixelization_routines import \
-    pixelize_cylinder, pixelize_cartesian
+
+from yt.utilities.lib.pixelization_routines import pixelize_cartesian, pixelize_cylinder
+
+from .coordinate_handler import CoordinateHandler, _get_coord_fields, _unknown_coord
+
 
 class GeographicCoordinateHandler(CoordinateHandler):
     radial_axis = "altitude"
@@ -492,4 +491,3 @@ def sanitize_width(self, axis, width, depth):
             outermost = factor * self.ds.domain_left_edge[ri] + offset
             width = [outermost, 2.0*outermost]
         return width
-
diff --git a/yt/geometry/coordinates/spec_cube_coordinates.py b/yt/geometry/coordinates/spec_cube_coordinates.py
index c162cdab079..45ba3070880 100644
--- a/yt/geometry/coordinates/spec_cube_coordinates.py
+++ b/yt/geometry/coordinates/spec_cube_coordinates.py
@@ -1,7 +1,6 @@
-from .cartesian_coordinates import \
-    CartesianCoordinateHandler
-from .coordinate_handler import \
-    _get_coord_fields
+from .cartesian_coordinates import CartesianCoordinateHandler
+from .coordinate_handler import _get_coord_fields
+
 
 class SpectralCubeCoordinateHandler(CartesianCoordinateHandler):
     name = "spectral_cube"
@@ -100,4 +99,3 @@ def convert_from_cylindrical(self, coord):
     @property
     def image_axis_name(self):
         return self._image_axis_name
-
diff --git a/yt/geometry/coordinates/spherical_coordinates.py b/yt/geometry/coordinates/spherical_coordinates.py
index c8e4498b205..867dc251c66 100644
--- a/yt/geometry/coordinates/spherical_coordinates.py
+++ b/yt/geometry/coordinates/spherical_coordinates.py
@@ -1,10 +1,9 @@
 import numpy as np
-from .coordinate_handler import \
-    CoordinateHandler, \
-    _unknown_coord, \
-    _get_coord_fields
-from yt.utilities.lib.pixelization_routines import \
-    pixelize_cylinder, pixelize_aitoff
+
+from yt.utilities.lib.pixelization_routines import pixelize_aitoff, pixelize_cylinder
+
+from .coordinate_handler import CoordinateHandler, _get_coord_fields, _unknown_coord
+
 
 class SphericalCoordinateHandler(CoordinateHandler):
     name = "spherical"
@@ -286,4 +285,3 @@ def _sanity_check(self):
         v2 = dd.quantities.total_quantity("cell_volume")
         print("Actual volume is                   %0.16e" % (v2))
         print("Relative difference: %0.16e" % (np.abs(v2-v1)/(v2+v1)))
-
diff --git a/yt/geometry/coordinates/tests/test_axial_pixelization.py b/yt/geometry/coordinates/tests/test_axial_pixelization.py
index 81c9186091a..fac56abe26f 100644
--- a/yt/geometry/coordinates/tests/test_axial_pixelization.py
+++ b/yt/geometry/coordinates/tests/test_axial_pixelization.py
@@ -1,7 +1,6 @@
-from yt.testing import \
-    fake_amr_ds, _geom_transforms
-from yt.utilities.answer_testing.framework import \
-    AxialPixelizationTest
+from yt.testing import _geom_transforms, fake_amr_ds
+from yt.utilities.answer_testing.framework import AxialPixelizationTest
+
 
 def test_axial_pixelization():
     for geom in sorted(_geom_transforms):
diff --git a/yt/geometry/coordinates/tests/test_cartesian_coordinates.py b/yt/geometry/coordinates/tests/test_cartesian_coordinates.py
index 5fe43cb20f1..805e9b26cfa 100644
--- a/yt/geometry/coordinates/tests/test_cartesian_coordinates.py
+++ b/yt/geometry/coordinates/tests/test_cartesian_coordinates.py
@@ -2,9 +2,7 @@
 
 import numpy as np
 
-from yt.testing import \
-    fake_amr_ds, \
-    assert_equal
+from yt.testing import assert_equal, fake_amr_ds
 
 # Our canonical tests are that we can access all of our fields and we can
 # compute our volume correctly.
diff --git a/yt/geometry/coordinates/tests/test_cylindrical_coordinates.py b/yt/geometry/coordinates/tests/test_cylindrical_coordinates.py
index 4983526b784..fdfec6c3825 100644
--- a/yt/geometry/coordinates/tests/test_cylindrical_coordinates.py
+++ b/yt/geometry/coordinates/tests/test_cylindrical_coordinates.py
@@ -2,14 +2,9 @@
 
 import numpy as np
 
-from yt.testing import \
-    fake_amr_ds, \
-    assert_equal, \
-    assert_almost_equal, \
-    add_noise_fields
-
-from yt.utilities.answer_testing.framework import GenericImageTest
 from yt import SlicePlot
+from yt.testing import add_noise_fields, assert_almost_equal, assert_equal, fake_amr_ds
+from yt.utilities.answer_testing.framework import GenericImageTest
 
 # Our canonical tests are that we can access all of our fields and we can
 # compute our volume correctly.
diff --git a/yt/geometry/coordinates/tests/test_geographic_coordinates.py b/yt/geometry/coordinates/tests/test_geographic_coordinates.py
index 7b71dd35753..46a574914bc 100644
--- a/yt/geometry/coordinates/tests/test_geographic_coordinates.py
+++ b/yt/geometry/coordinates/tests/test_geographic_coordinates.py
@@ -2,10 +2,7 @@
 
 import numpy as np
 
-from yt.testing import \
-    fake_amr_ds, \
-    assert_equal, \
-    assert_rel_equal
+from yt.testing import assert_equal, assert_rel_equal, fake_amr_ds
 
 # Our canonical tests are that we can access all of our fields and we can
 # compute our volume correctly.
diff --git a/yt/geometry/coordinates/tests/test_polar_coordinates.py b/yt/geometry/coordinates/tests/test_polar_coordinates.py
index 5356f7b9adb..97f1738995f 100644
--- a/yt/geometry/coordinates/tests/test_polar_coordinates.py
+++ b/yt/geometry/coordinates/tests/test_polar_coordinates.py
@@ -3,10 +3,7 @@
 
 import numpy as np
 
-from yt.testing import \
-    fake_amr_ds, \
-    assert_equal, \
-    assert_almost_equal
+from yt.testing import assert_almost_equal, assert_equal, fake_amr_ds
 
 # Our canonical tests are that we can access all of our fields and we can
 # compute our volume correctly.
diff --git a/yt/geometry/coordinates/tests/test_spherical_coordinates.py b/yt/geometry/coordinates/tests/test_spherical_coordinates.py
index aa15db698ca..9947669cded 100644
--- a/yt/geometry/coordinates/tests/test_spherical_coordinates.py
+++ b/yt/geometry/coordinates/tests/test_spherical_coordinates.py
@@ -2,10 +2,7 @@
 
 import numpy as np
 
-from yt.testing import \
-    fake_amr_ds, \
-    assert_equal, \
-    assert_almost_equal
+from yt.testing import assert_almost_equal, assert_equal, fake_amr_ds
 
 # Our canonical tests are that we can access all of our fields and we can
 # compute our volume correctly.
diff --git a/yt/geometry/geometry_handler.py b/yt/geometry/geometry_handler.py
index 56dae3313dd..3e267c24f6e 100644
--- a/yt/geometry/geometry_handler.py
+++ b/yt/geometry/geometry_handler.py
@@ -1,18 +1,21 @@
 import os
 import pickle
 import weakref
-from yt.utilities.on_demand_imports import _h5py as h5py
+
 import numpy as np
 
 from yt.config import ytcfg
 from yt.funcs import iterable
-from yt.units.yt_array import \
-    YTArray, uconcatenate
+from yt.units.yt_array import YTArray, uconcatenate
+from yt.utilities.exceptions import YTFieldNotFound
 from yt.utilities.io_handler import io_registry
 from yt.utilities.logger import ytLogger as mylog
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    ParallelAnalysisInterface, parallel_root_only
-from yt.utilities.exceptions import YTFieldNotFound
+from yt.utilities.on_demand_imports import _h5py as h5py
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    ParallelAnalysisInterface,
+    parallel_root_only,
+)
+
 
 class Index(ParallelAnalysisInterface):
     """The base index class"""
@@ -433,4 +436,4 @@ def is_curvilinear(geo):
     if geo in ["polar", "cylindrical", "spherical"]:
         return True
     else:
-        return False
\ No newline at end of file
+        return False
diff --git a/yt/geometry/grid_geometry_handler.py b/yt/geometry/grid_geometry_handler.py
index f176e124e4f..04e823e0417 100644
--- a/yt/geometry/grid_geometry_handler.py
+++ b/yt/geometry/grid_geometry_handler.py
@@ -1,21 +1,19 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
-import numpy as np
 import weakref
-
 from collections import defaultdict
 
+import numpy as np
+
 from yt.arraytypes import blankRecordArray
 from yt.config import ytcfg
 from yt.fields.derived_field import ValidateSpatial
 from yt.fields.field_detector import FieldDetector
-from yt.funcs import \
-    ensure_list, ensure_numpy_array
-from yt.geometry.geometry_handler import \
-    Index, YTDataChunk, ChunkDataCache
+from yt.funcs import ensure_list, ensure_numpy_array
+from yt.geometry.geometry_handler import ChunkDataCache, Index, YTDataChunk
 from yt.utilities.definitions import MAXLEVEL
 from yt.utilities.logger import ytLogger as mylog
-from .grid_container import \
-    GridTree, MatchPointsToGrids
+from yt.utilities.on_demand_imports import _h5py as h5py
+
+from .grid_container import GridTree, MatchPointsToGrids
 
 
 class GridIndex(Index):
diff --git a/yt/geometry/object_finding_mixin.py b/yt/geometry/object_finding_mixin.py
index 8941ba17fd6..1492a1006e4 100644
--- a/yt/geometry/object_finding_mixin.py
+++ b/yt/geometry/object_finding_mixin.py
@@ -1,17 +1,12 @@
 import numpy as np
 
 from yt.config import ytcfg
-from yt.funcs import \
-    mylog, ensure_numpy_array, \
-    ensure_list
-from yt.utilities.lib.misc_utilities import \
-    get_box_grids_below_level
-from yt.geometry.grid_container import \
-    MatchPointsToGrids, \
-    GridTree
-from yt.utilities.physical_ratios import \
-    HUGE
+from yt.funcs import ensure_list, ensure_numpy_array, mylog
+from yt.geometry.grid_container import GridTree, MatchPointsToGrids
 from yt.utilities.exceptions import YTTooParallel
+from yt.utilities.lib.misc_utilities import get_box_grids_below_level
+from yt.utilities.physical_ratios import HUGE
+
 
 class ObjectFindingMixin :
 
diff --git a/yt/geometry/oct_geometry_handler.py b/yt/geometry/oct_geometry_handler.py
index 7289f7f87d6..4f97a50967b 100644
--- a/yt/geometry/oct_geometry_handler.py
+++ b/yt/geometry/oct_geometry_handler.py
@@ -1,7 +1,8 @@
 import numpy as np
-from yt.utilities.logger import ytLogger as mylog
-from yt.geometry.geometry_handler import Index
+
 from yt.fields.field_detector import FieldDetector
+from yt.geometry.geometry_handler import Index
+from yt.utilities.logger import ytLogger as mylog
 
 
 class OctreeIndex(Index):
@@ -99,4 +100,3 @@ def _mesh_sampling_particle_field(field, data):
             sampling_type="particle",
             units=units,
             take_log=take_log)
-
diff --git a/yt/geometry/particle_geometry_handler.py b/yt/geometry/particle_geometry_handler.py
index 197a32e0a19..79d57c2617e 100644
--- a/yt/geometry/particle_geometry_handler.py
+++ b/yt/geometry/particle_geometry_handler.py
@@ -1,20 +1,17 @@
 import collections
 import errno
-import numpy as np
 import os
-import weakref
 import struct
+import weakref
+
+import numpy as np
 
-from yt.funcs import \
-    get_pbar, \
-    only_on_root
-from yt.utilities.logger import ytLogger as mylog
-from yt.geometry.geometry_handler import \
-    Index, \
-    YTDataChunk
-from yt.geometry.particle_oct_container import ParticleBitmap
 from yt.data_objects.particle_container import ParticleContainer
+from yt.funcs import get_pbar, only_on_root
+from yt.geometry.geometry_handler import Index, YTDataChunk
+from yt.geometry.particle_oct_container import ParticleBitmap
 from yt.utilities.lib.fnv_hash import fnv_hash
+from yt.utilities.logger import ytLogger as mylog
 
 CHUNKSIZE = 64**3
 
diff --git a/yt/geometry/tests/fake_octree.py b/yt/geometry/tests/fake_octree.py
index 5622d018688..058a926427c 100644
--- a/yt/geometry/tests/fake_octree.py
+++ b/yt/geometry/tests/fake_octree.py
@@ -1,7 +1,8 @@
-from yt.geometry.fake_octree import create_fake_octree
-from yt.geometry.oct_container import RAMSESOctreeContainer, ParticleOctreeContainer
 import numpy as np
 
+from yt.geometry.fake_octree import create_fake_octree
+from yt.geometry.oct_container import ParticleOctreeContainer, RAMSESOctreeContainer
+
 nocts= 3
 max_level = 12
 dn = 2
diff --git a/yt/geometry/tests/test_grid_container.py b/yt/geometry/tests/test_grid_container.py
index a8dd8f653cf..d5d67990888 100644
--- a/yt/geometry/tests/test_grid_container.py
+++ b/yt/geometry/tests/test_grid_container.py
@@ -1,10 +1,9 @@
-import numpy as np
 import random
 
-from yt.testing import \
-    assert_equal, assert_raises
-from yt.frontends.stream.api import \
-    load_amr_grids
+import numpy as np
+
+from yt.frontends.stream.api import load_amr_grids
+from yt.testing import assert_equal, assert_raises
 
 
 def setup_test_ds():
diff --git a/yt/geometry/tests/test_neighbor_search.py b/yt/geometry/tests/test_neighbor_search.py
index 191ae3db1d8..d3abd71aa6d 100644
--- a/yt/geometry/tests/test_neighbor_search.py
+++ b/yt/geometry/tests/test_neighbor_search.py
@@ -1,11 +1,7 @@
 import numpy as np
 
-from yt.fields.particle_fields import \
-    add_nearest_neighbor_field
-from yt.testing import \
-    fake_particle_ds, \
-    assert_equal, \
-    assert_array_almost_equal
+from yt.fields.particle_fields import add_nearest_neighbor_field
+from yt.testing import assert_array_almost_equal, assert_equal, fake_particle_ds
 
 
 def test_neighbor_search():
diff --git a/yt/geometry/tests/test_particle_deposit.py b/yt/geometry/tests/test_particle_deposit.py
index 840660221db..7e333c03a5b 100644
--- a/yt/geometry/tests/test_particle_deposit.py
+++ b/yt/geometry/tests/test_particle_deposit.py
@@ -1,14 +1,9 @@
-from yt.utilities.exceptions import \
-    YTBoundsDefinitionError
-
-from yt.convenience import \
-    load
-from yt.testing import \
-    fake_random_ds, \
-    requires_file
-from numpy.testing import \
-    assert_raises, assert_array_less, assert_allclose
+from numpy.testing import assert_allclose, assert_array_less, assert_raises
+
 import yt
+from yt.convenience import load
+from yt.testing import fake_random_ds, requires_file
+from yt.utilities.exceptions import YTBoundsDefinitionError
 
 
 def test_cic_deposit():
diff --git a/yt/geometry/tests/test_particle_octree.py b/yt/geometry/tests/test_particle_octree.py
index 0e193c845b5..0b337effc83 100644
--- a/yt/geometry/tests/test_particle_octree.py
+++ b/yt/geometry/tests/test_particle_octree.py
@@ -1,24 +1,21 @@
 
-import numpy as np
 import os
 
-from yt.geometry.particle_oct_container import \
-    ParticleOctreeContainer, \
-    ParticleBitmap
+import numpy as np
+
+import yt.units.dimensions as dimensions
 from yt.geometry.oct_container import _ORDER_MAX
+from yt.geometry.particle_oct_container import ParticleBitmap, ParticleOctreeContainer
 from yt.geometry.selection_routines import RegionSelector
-from yt.testing import \
-    assert_equal, \
-    assert_true, \
-    assert_array_equal
+from yt.testing import assert_array_equal, assert_equal, assert_true
 from yt.units.unit_registry import UnitRegistry
 from yt.units.yt_array import YTArray
-from yt.utilities.lib.geometry_utils import get_morton_indices, \
-    get_morton_points, \
-    get_hilbert_points, \
-    get_hilbert_indices
-
-import yt.units.dimensions as dimensions
+from yt.utilities.lib.geometry_utils import (
+    get_hilbert_indices,
+    get_hilbert_points,
+    get_morton_indices,
+    get_morton_points,
+)
 
 NPART = 32**3
 DLE = np.array([0.0, 0.0, 0.0])
diff --git a/yt/geometry/unstructured_mesh_handler.py b/yt/geometry/unstructured_mesh_handler.py
index 82110885f67..35ece25a147 100644
--- a/yt/geometry/unstructured_mesh_handler.py
+++ b/yt/geometry/unstructured_mesh_handler.py
@@ -1,10 +1,12 @@
-import numpy as np
 import os
 import weakref
 
-from yt.utilities.logger import ytLogger as mylog
+import numpy as np
+
 from yt.geometry.geometry_handler import Index, YTDataChunk
 from yt.utilities.lib.mesh_utilities import smallest_fwidth
+from yt.utilities.logger import ytLogger as mylog
+
 
 class UnstructuredIndex(Index):
     """The Index subclass for unstructured and hexahedral mesh datasets. """
diff --git a/yt/mods.py b/yt/mods.py
index 53b24bfeffe..000a7d990b8 100644
--- a/yt/mods.py
+++ b/yt/mods.py
@@ -3,7 +3,6 @@
 #
 
 import os
-from yt import *
 
 # This next item will handle most of the actual startup procedures, but it will
 # also attempt to parse the command line and set up the global state of various
@@ -11,11 +10,13 @@
 # provided as a convenience for users who wish to parse arguments in scripts.
 # https://mail.python.org/archives/list/yt-dev@python.org/thread/L6AQPJ3OIMJC5SNKVM7CJG32YVQZRJWA/
 import yt.startup_tasks as __startup_tasks
+from yt import *
+from yt.config import ytcfg, ytcfg_defaults
+from yt.utilities.logger import level as __level
+
 unparsed_args = __startup_tasks.unparsed_args
 
-from yt.config import ytcfg, ytcfg_defaults
 
-from yt.utilities.logger import level as __level
 if __level >= int(ytcfg_defaults["loglevel"]):
     # This won't get displayed.
     mylog.debug("Turning off NumPy error reporting")
diff --git a/yt/pmods.py b/yt/pmods.py
index 282722dd3fb..131f2fa1f13 100644
--- a/yt/pmods.py
+++ b/yt/pmods.py
@@ -193,10 +193,11 @@ def bcast(obj=None,root=0):
 """
 
 
-import sys
+import builtins
 import imp
+import sys
 import types
-import builtins
+
 from mpi4py import MPI
 
 
diff --git a/yt/startup_tasks.py b/yt/startup_tasks.py
index 649d52becf0..f8bb92719b8 100644
--- a/yt/startup_tasks.py
+++ b/yt/startup_tasks.py
@@ -2,16 +2,17 @@
 
 import argparse
 import os
-import sys
 import signal
+import sys
 
 from yt.config import ytcfg
-from yt.funcs import \
-    mylog, \
-    signal_print_traceback, \
-    signal_ipython, \
-    paste_traceback, \
-    paste_traceback_detailed
+from yt.funcs import (
+    mylog,
+    paste_traceback,
+    paste_traceback_detailed,
+    signal_ipython,
+    signal_print_traceback,
+)
 from yt.utilities import rpdb
 
 exe_name = os.path.basename(sys.executable)
diff --git a/yt/testing.py b/yt/testing.py
index 2b64b1fec45..89e6a249498 100644
--- a/yt/testing.py
+++ b/yt/testing.py
@@ -1,16 +1,24 @@
-import hashlib
-import matplotlib
-import pickle
-import itertools as it
-import numpy as np
 import functools
+import hashlib
 import importlib
+import itertools as it
 import os
+import pickle
 import shutil
 import tempfile
 import unittest
-from yt.funcs import iterable
+
+import matplotlib
+import numpy as np
+from numpy.random import RandomState
+from unyt.exceptions import UnitOperationError
+
+import yt
 from yt.config import ytcfg
+from yt.convenience import load
+from yt.funcs import iterable
+from yt.units.yt_array import YTArray, YTQuantity
+
 # we import this in a weird way from numpy.testing to avoid triggering
 # flake8 errors from the unused imports. These test functions are imported
 # elsewhere in yt from here so we want them to be imported here.
@@ -20,11 +28,6 @@
 from numpy.testing import assert_string_equal  # NOQA isort:skip
 from numpy.testing import assert_array_almost_equal_nulp  # NOQA isort:skip
 from numpy.testing import assert_allclose, assert_raises  # NOQA isort:skip
-from numpy.random import RandomState
-from yt.convenience import load
-from yt.units.yt_array import YTArray, YTQuantity
-from unyt.exceptions import UnitOperationError
-import yt
 
 ANSWER_TEST_TAG = "answer_test"
 # Expose assert_true and assert_less_equal from unittest.TestCase
diff --git a/yt/tests/test_load_from_path.py b/yt/tests/test_load_from_path.py
index 86272e03491..a9b36e60c61 100644
--- a/yt/tests/test_load_from_path.py
+++ b/yt/tests/test_load_from_path.py
@@ -1,8 +1,10 @@
 import os
 from sys import version_info
-from yt.convenience import _sanitize_load_args
+
 import pytest
 
+from yt.convenience import _sanitize_load_args
+
 PY36 = version_info >= (3, 6)
 
 if PY36:
diff --git a/yt/tests/test_testing.py b/yt/tests/test_testing.py
index aeab7f5ddc8..cc26240d0e6 100644
--- a/yt/tests/test_testing.py
+++ b/yt/tests/test_testing.py
@@ -2,8 +2,8 @@
 import numpy as np
 import pytest
 
-from yt.testing import assert_equal, requires_backend
 import yt
+from yt.testing import assert_equal, requires_backend
 
 
 def test_requires_backend():
diff --git a/yt/units/__init__.py b/yt/units/__init__.py
index d98507c5d54..a1d0b84b5ff 100644
--- a/yt/units/__init__.py
+++ b/yt/units/__init__.py
@@ -1,6 +1,3 @@
-from yt.units.physical_constants import *
-from yt.units.unit_symbols import *
-from yt.utilities.exceptions import YTArrayTooLargeToDisplay
 from unyt.array import (
     loadtxt,
     savetxt,
@@ -10,22 +7,26 @@
     uhstack,
     uintersect1d,
     unorm,
+    unyt_array,
+    unyt_quantity,
     ustack,
     uunion1d,
     uvstack,
-    unyt_array,
-    unyt_quantity,
 )
 from unyt.unit_object import Unit, define_unit  # NOQA: F401
 from unyt.unit_registry import UnitRegistry  # NOQA: Ffg401
 from unyt.unit_systems import UnitSystem  # NOQA: F401
 
+from yt.units.physical_constants import *
+from yt.units.physical_constants import _ConstantContainer
+from yt.units.unit_symbols import *
+from yt.units.unit_symbols import _SymbolContainer
+from yt.utilities.exceptions import YTArrayTooLargeToDisplay
+
 YTArray = unyt_array
 
 YTQuantity = unyt_quantity
 
-from yt.units.unit_symbols import _SymbolContainer
-from yt.units.physical_constants import _ConstantContainer
 
 class UnitContainer:
     """A container for units and constants to associate with a dataset
@@ -111,4 +112,3 @@ def _value_updater(change):
 def _wrap_display_ytarray(arr):
     from IPython.core.display import display
     display(display_ytarray(arr))
-
diff --git a/yt/units/physical_constants.py b/yt/units/physical_constants.py
index a0e62962787..10ddb4c2457 100644
--- a/yt/units/physical_constants.py
+++ b/yt/units/physical_constants.py
@@ -1,7 +1,8 @@
-from yt.units.unit_registry import default_unit_registry
 from unyt.array import unyt_quantity
 from unyt.unit_systems import add_constants
 
+from yt.units.unit_registry import default_unit_registry
+
 add_constants(globals(), registry=default_unit_registry)
 
 class _ConstantContainer:
diff --git a/yt/units/tests/test_magnetic_code_units.py b/yt/units/tests/test_magnetic_code_units.py
index b335a35951b..148c28f2aa6 100644
--- a/yt/units/tests/test_magnetic_code_units.py
+++ b/yt/units/tests/test_magnetic_code_units.py
@@ -1,7 +1,9 @@
 import numpy as np
+
 from yt.frontends.stream.api import load_uniform_grid
 from yt.testing import assert_allclose
 
+
 def test_magnetic_code_units():
 
     sqrt4pi = np.sqrt(4.0*np.pi)
diff --git a/yt/units/unit_registry.py b/yt/units/unit_registry.py
index 89ff3cdfa61..24b8888dd04 100644
--- a/yt/units/unit_registry.py
+++ b/yt/units/unit_registry.py
@@ -1,5 +1,5 @@
-from unyt.unit_registry import *
 from unyt.dimensions import dimensionless
+from unyt.unit_registry import *
 
 default_unit_registry = UnitRegistry(unit_system='cgs')
 
diff --git a/yt/units/unit_symbols.py b/yt/units/unit_symbols.py
index 8e86e76273a..75366e4ddcf 100644
--- a/yt/units/unit_symbols.py
+++ b/yt/units/unit_symbols.py
@@ -1,7 +1,8 @@
-from yt.units.unit_registry import default_unit_registry
 from unyt.unit_object import Unit
 from unyt.unit_systems import add_symbols
 
+from yt.units.unit_registry import default_unit_registry
+
 add_symbols(globals(), registry=default_unit_registry)
 
 class _SymbolContainer:
@@ -46,4 +47,3 @@ def __getattr__(self, item):
             raise AttributeError(item)
         self._cache[item] = ret
         return ret
-
diff --git a/yt/units/unit_systems.py b/yt/units/unit_systems.py
index 184a05c2f3c..94db6c00ba5 100644
--- a/yt/units/unit_systems.py
+++ b/yt/units/unit_systems.py
@@ -1,5 +1,6 @@
 from unyt.unit_systems import *
 
+
 def create_code_unit_system(unit_registry, current_mks_unit=None):
     code_unit_system = UnitSystem(unit_registry.unit_system_id, "code_length",
                                   "code_mass", "code_time", "code_temperature",
diff --git a/yt/units/yt_array.py b/yt/units/yt_array.py
index d26b52c4faf..b5a65be316d 100644
--- a/yt/units/yt_array.py
+++ b/yt/units/yt_array.py
@@ -1,6 +1,8 @@
 from unyt.array import *
-from yt.units import YTArray, YTQuantity
+
 from yt.funcs import array_like_field
+from yt.units import YTArray, YTQuantity
+
 
 def display_ytarray(arr):
     r"""
diff --git a/yt/utilities/amr_kdtree/__init__.py b/yt/utilities/amr_kdtree/__init__.py
index 06cde376cf3..a8f6ee350cb 100644
--- a/yt/utilities/amr_kdtree/__init__.py
+++ b/yt/utilities/amr_kdtree/__init__.py
@@ -2,4 +2,3 @@
 Initialize amr_kdtree
 
 """
-
diff --git a/yt/utilities/amr_kdtree/amr_kdtools.py b/yt/utilities/amr_kdtree/amr_kdtools.py
index 78e7a53de14..9064ee7603a 100644
--- a/yt/utilities/amr_kdtree/amr_kdtools.py
+++ b/yt/utilities/amr_kdtree/amr_kdtools.py
@@ -1,4 +1,5 @@
 import numpy as np
+
 from yt.funcs import mylog
 
 
diff --git a/yt/utilities/amr_kdtree/amr_kdtree.py b/yt/utilities/amr_kdtree/amr_kdtree.py
index 4ba78eb133c..a23e6ff2c74 100644
--- a/yt/utilities/amr_kdtree/amr_kdtree.py
+++ b/yt/utilities/amr_kdtree/amr_kdtree.py
@@ -1,20 +1,21 @@
 import operator
+
 import numpy as np
 
-from yt.funcs import \
-    iterable, \
-    mylog
-from yt.utilities.on_demand_imports import _h5py as h5py
-from yt.utilities.amr_kdtree.amr_kdtools import \
-    receive_and_reduce, \
-    send_to_parent, \
-    scatter_image
+from yt.funcs import iterable, mylog
+from yt.geometry.grid_geometry_handler import GridIndex
+from yt.utilities.amr_kdtree.amr_kdtools import (
+    receive_and_reduce,
+    scatter_image,
+    send_to_parent,
+)
 from yt.utilities.lib.amr_kdtools import Node
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    ParallelAnalysisInterface
 from yt.utilities.lib.partitioned_grid import PartitionedGrid
 from yt.utilities.math_utils import periodic_position
-from yt.geometry.grid_geometry_handler import GridIndex
+from yt.utilities.on_demand_imports import _h5py as h5py
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    ParallelAnalysisInterface,
+)
 
 steps = np.array([[-1, -1, -1], [-1, -1,  0], [-1, -1,  1],
                   [-1,  0, -1], [-1,  0,  0], [-1,  0,  1],
diff --git a/yt/utilities/answer_testing/__init__.py b/yt/utilities/answer_testing/__init__.py
index 81c61259ce7..a486d483f56 100644
--- a/yt/utilities/answer_testing/__init__.py
+++ b/yt/utilities/answer_testing/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/utilities/answer_testing/answer_tests.py b/yt/utilities/answer_testing/answer_tests.py
index 5a888a0640f..d85133f5bf1 100644
--- a/yt/utilities/answer_testing/answer_tests.py
+++ b/yt/utilities/answer_testing/answer_tests.py
@@ -2,16 +2,17 @@
 Title: answer_tests.py
 Purpose: Contains answer tests that are used by yt's various frontends
 """
+import hashlib
 import os
 import tempfile
 
-import hashlib
 import matplotlib.image as mpimg
 import numpy as np
 
-from . import utils
 import yt.visualization.plot_window as pw
 
+from . import utils
+
 
 def grid_hierarchy(ds):
     result = {}
diff --git a/yt/utilities/answer_testing/api.py b/yt/utilities/answer_testing/api.py
index 536df4d5171..e5900babeb4 100644
--- a/yt/utilities/answer_testing/api.py
+++ b/yt/utilities/answer_testing/api.py
@@ -1,2 +1 @@
 from yt.utilities.answer_testing.framework import AnswerTesting
-
diff --git a/yt/utilities/answer_testing/framework.py b/yt/utilities/answer_testing/framework.py
index 56464fa76eb..9e9cbbd3332 100644
--- a/yt/utilities/answer_testing/framework.py
+++ b/yt/utilities/answer_testing/framework.py
@@ -2,47 +2,47 @@
 Title: framework.py
 Purpose: Contains answer tests that are used by yt's various frontends
 """
+import contextlib
+import glob
+import hashlib
 import logging
-import numpy as np
 import os
-import time
-import hashlib
-import contextlib
-import sys
 import pickle
-import urllib
 import shelve
-import zlib
+import sys
 import tempfile
-import glob
-
+import time
+import urllib
+import zlib
 from collections import defaultdict
 
+import matplotlib.image as mpimg
+import numpy as np
 from matplotlib.testing.compare import compare_images
 from nose.plugins import Plugin
-from yt.funcs import \
-    get_pbar
-from yt.testing import \
-    assert_equal, \
-    assert_allclose_units, \
-    assert_rel_equal, \
-    assert_almost_equal
-from yt.convenience import load, simulation
+
+import yt.visualization.particle_plots as particle_plots
+import yt.visualization.plot_window as pw
+import yt.visualization.profile_plotter as profile_plotter
 from yt.config import ytcfg
+from yt.convenience import load, simulation
 from yt.data_objects.static_output import Dataset
 from yt.data_objects.time_series import SimulationTimeSeries
-from yt.utilities.exceptions import \
-    YTNoOldAnswer, \
-    YTCloudError, \
-    YTOutputNotIdentified, \
-    YTNoAnswerNameSpecified
-from yt.utilities.logger import disable_stream_logging
+from yt.funcs import get_pbar
+from yt.testing import (
+    assert_allclose_units,
+    assert_almost_equal,
+    assert_equal,
+    assert_rel_equal,
+)
 from yt.utilities.command_line import get_yt_version
-
-import matplotlib.image as mpimg
-import yt.visualization.plot_window as pw
-import yt.visualization.particle_plots as particle_plots
-import yt.visualization.profile_plotter as profile_plotter
+from yt.utilities.exceptions import (
+    YTCloudError,
+    YTNoAnswerNameSpecified,
+    YTNoOldAnswer,
+    YTOutputNotIdentified,
+)
+from yt.utilities.logger import disable_stream_logging
 
 mylog = logging.getLogger('nose.plugins.answer-testing')
 run_big_data = False
diff --git a/yt/utilities/answer_testing/level_sets_tests.py b/yt/utilities/answer_testing/level_sets_tests.py
index 652627d67a8..40fd7f4ad81 100644
--- a/yt/utilities/answer_testing/level_sets_tests.py
+++ b/yt/utilities/answer_testing/level_sets_tests.py
@@ -1,9 +1,8 @@
 import numpy as np
 
-from yt.testing import \
-    assert_equal
-from yt.utilities.answer_testing.framework import \
-    AnswerTestingTest
+from yt.testing import assert_equal
+from yt.utilities.answer_testing.framework import AnswerTestingTest
+
 
 class ExtractConnectedSetsTest(AnswerTestingTest):
     _type_name = "ExtractConnectedSets"
diff --git a/yt/utilities/answer_testing/utils.py b/yt/utilities/answer_testing/utils.py
index 8851cf8daf2..e3380846b2a 100644
--- a/yt/utilities/answer_testing/utils.py
+++ b/yt/utilities/answer_testing/utils.py
@@ -12,19 +12,16 @@
 import pytest
 import yaml
 
+import yt.visualization.particle_plots as particle_plots
+import yt.visualization.plot_window as pw
+import yt.visualization.profile_plotter as profile_plotter
 from yt.config import ytcfg
 from yt.convenience import load, simulation
 from yt.data_objects.selection_data_containers import YTRegion
 from yt.data_objects.static_output import Dataset
 from yt.frontends.ytdata.api import save_as_dataset
-from yt.units.yt_array import \
-    YTArray, \
-    YTQuantity
-from yt.utilities.exceptions import \
-    YTOutputNotIdentified
-import yt.visualization.particle_plots as particle_plots
-import yt.visualization.plot_window as pw
-import yt.visualization.profile_plotter as profile_plotter
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.exceptions import YTOutputNotIdentified
 from yt.visualization.volume_rendering.scene import Scene
 
 
diff --git a/yt/utilities/api.py b/yt/utilities/api.py
index 7c097dfc5f5..66de06ca695 100644
--- a/yt/utilities/api.py
+++ b/yt/utilities/api.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/utilities/chemical_formulas.py b/yt/utilities/chemical_formulas.py
index 4f199ae6c8d..63dc2ea6f0e 100644
--- a/yt/utilities/chemical_formulas.py
+++ b/yt/utilities/chemical_formulas.py
@@ -1,4 +1,5 @@
 import re
+
 from .periodic_table import periodic_table
 from .physical_ratios import _primordial_mass_fraction
 
diff --git a/yt/utilities/command_line.py b/yt/utilities/command_line.py
index a664e044ffa..6dd5a02ece0 100644
--- a/yt/utilities/command_line.py
+++ b/yt/utilities/command_line.py
@@ -1,40 +1,44 @@
 import argparse
 import base64
 import getpass
-import numpy as np
+import json
 import os
-import sys
+import pprint
 import subprocess
+import sys
 import tempfile
-import json
-import pprint
 import textwrap
-
-from yt.config import ytcfg, CURRENT_CONFIG_FILE
-ytcfg["yt","__command_line"] = "True"
-from yt.startup_tasks import parser, subparsers
-from yt.funcs import \
-    ensure_dir, \
-    ensure_list, \
-    get_hg_or_git_version, \
-    get_yt_version, \
-    mylog, \
-    ensure_dir_exists, \
-    update_hg_or_git, \
-    enable_plugins, \
-    download_file
 import urllib
 import urllib.request
 from urllib.parse import urlparse
-from yt.extern.tqdm import tqdm
+
+import numpy as np
+
+from yt.config import CURRENT_CONFIG_FILE, ytcfg
 from yt.convenience import load
-from yt.visualization.plot_window import \
-    SlicePlot, \
-    ProjectionPlot
-from yt.utilities.metadata import get_metadata
+from yt.extern.tqdm import tqdm
+from yt.funcs import (
+    download_file,
+    enable_plugins,
+    ensure_dir,
+    ensure_dir_exists,
+    ensure_list,
+    get_hg_or_git_version,
+    get_yt_version,
+    mylog,
+    update_hg_or_git,
+)
+from yt.startup_tasks import parser, subparsers
 from yt.utilities.configure import set_config
-from yt.utilities.exceptions import \
-    YTOutputNotIdentified, YTFieldNotParseable, YTCommandRequiresModule
+from yt.utilities.exceptions import (
+    YTCommandRequiresModule,
+    YTFieldNotParseable,
+    YTOutputNotIdentified,
+)
+from yt.utilities.metadata import get_metadata
+from yt.visualization.plot_window import ProjectionPlot, SlicePlot
+
+ytcfg["yt","__command_line"] = "True"
 
 # loading field plugins for backward compatibility, since this module
 # used to do "from yt.mods import *"
diff --git a/yt/utilities/configure.py b/yt/utilities/configure.py
index 8fbd8ba5aed..423e1848714 100644
--- a/yt/utilities/configure.py
+++ b/yt/utilities/configure.py
@@ -1,9 +1,10 @@
+import argparse
+import configparser
 import os
 import shutil
 import sys
-import argparse
-from yt.config import CURRENT_CONFIG_FILE, _OLD_CONFIG_FILE, YTConfigParser
-import configparser
+
+from yt.config import _OLD_CONFIG_FILE, CURRENT_CONFIG_FILE, YTConfigParser
 
 CONFIG = YTConfigParser()
 CONFIG.read([CURRENT_CONFIG_FILE])
diff --git a/yt/utilities/cosmology.py b/yt/utilities/cosmology.py
index 4287a4904e3..f4e6923a9e0 100644
--- a/yt/utilities/cosmology.py
+++ b/yt/utilities/cosmology.py
@@ -1,20 +1,17 @@
 import functools
+
 import numpy as np
 
-from yt.funcs import \
-    issue_deprecation_warning
+from yt.funcs import issue_deprecation_warning
 from yt.units import dimensions
-from yt.units.unit_registry import \
-    UnitRegistry
-from yt.units.unit_object import \
-    Unit
-from yt.units.yt_array import \
-    YTArray, \
-    YTQuantity
-
-from yt.utilities.physical_constants import \
-     gravitational_constant_cgs as G, \
-     speed_of_light_cgs
+from yt.units.unit_object import Unit
+from yt.units.unit_registry import UnitRegistry
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.physical_constants import (
+    gravitational_constant_cgs as G,
+    speed_of_light_cgs,
+)
+
 
 class Cosmology:
     r"""
diff --git a/yt/utilities/definitions.py b/yt/utilities/definitions.py
index 76ff06878e6..af2f39749bf 100644
--- a/yt/utilities/definitions.py
+++ b/yt/utilities/definitions.py
@@ -1,7 +1,17 @@
-from .physical_ratios import \
-   mpc_per_mpc, kpc_per_mpc, pc_per_mpc, au_per_mpc, rsun_per_mpc, \
-   miles_per_mpc, km_per_mpc, cm_per_mpc, sec_per_Gyr, sec_per_Myr, \
-   sec_per_year, sec_per_day
+from .physical_ratios import (
+    au_per_mpc,
+    cm_per_mpc,
+    km_per_mpc,
+    kpc_per_mpc,
+    miles_per_mpc,
+    mpc_per_mpc,
+    pc_per_mpc,
+    rsun_per_mpc,
+    sec_per_day,
+    sec_per_Gyr,
+    sec_per_Myr,
+    sec_per_year,
+)
 
 # The number of levels we expect to have at most
 MAXLEVEL=48
diff --git a/yt/utilities/exceptions.py b/yt/utilities/exceptions.py
index 7761e6e5b99..514fe8049ed 100644
--- a/yt/utilities/exceptions.py
+++ b/yt/utilities/exceptions.py
@@ -4,6 +4,7 @@
 
 from unyt.exceptions import UnitOperationError
 
+
 class YTException(Exception):
     def __init__(self, message = None, ds = None):
         Exception.__init__(self, message)
diff --git a/yt/utilities/file_handler.py b/yt/utilities/file_handler.py
index 462e9fd60f3..39badcf0cc3 100644
--- a/yt/utilities/file_handler.py
+++ b/yt/utilities/file_handler.py
@@ -1,7 +1,7 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
-from yt.utilities.on_demand_imports import NotAModule
 from contextlib import contextmanager
 
+from yt.utilities.on_demand_imports import NotAModule, _h5py as h5py
+
 
 def valid_hdf5_signature(fn):
     signature = b'\x89HDF\r\n\x1a\n'
diff --git a/yt/utilities/fits_image.py b/yt/utilities/fits_image.py
index 6e7d8e8b443..df001abd8b6 100644
--- a/yt/utilities/fits_image.py
+++ b/yt/utilities/fits_image.py
@@ -1,9 +1,12 @@
 from yt.funcs import issue_deprecation_warning
+from yt.visualization.fits_image import (
+    FITSImageData,
+    FITSOffAxisProjection,
+    FITSOffAxisSlice,
+    FITSProjection,
+    FITSSlice,
+)
 
 issue_deprecation_warning("The fits_image classes have been moved to yt.visualization "
                           "and can be imported from yt directly. yt.utilities.fits_image "
                           "is deprecated.")
-
-from yt.visualization.fits_image import \
-    FITSImageData, FITSSlice, FITSProjection, \
-    FITSOffAxisSlice, FITSOffAxisProjection
\ No newline at end of file
diff --git a/yt/utilities/flagging_methods.py b/yt/utilities/flagging_methods.py
index 1689ccaafa8..8bfc47ca70b 100644
--- a/yt/utilities/flagging_methods.py
+++ b/yt/utilities/flagging_methods.py
@@ -1,4 +1,5 @@
-import numpy as np # For modern purposes
+import numpy as np  # For modern purposes
+
 from yt.utilities.lib.misc_utilities import grow_flagging_field
 
 flagging_method_registry = {}
diff --git a/yt/utilities/fortran_utils.py b/yt/utilities/fortran_utils.py
index c727274a503..465dfd28839 100644
--- a/yt/utilities/fortran_utils.py
+++ b/yt/utilities/fortran_utils.py
@@ -1,6 +1,7 @@
+import os
 import struct
+
 import numpy as np
-import os
 
 # This may not be the correct way to do this.  We should investigate what NumPy
 # does.
diff --git a/yt/utilities/grid_data_format/conversion/__init__.py b/yt/utilities/grid_data_format/conversion/__init__.py
index 92bf27bc04a..d844769a3d8 100644
--- a/yt/utilities/grid_data_format/conversion/__init__.py
+++ b/yt/utilities/grid_data_format/conversion/__init__.py
@@ -1,2 +1,2 @@
 from .conversion_abc import Converter
-from .conversion_athena import AthenaDistributedConverter, AthenaConverter
+from .conversion_athena import AthenaConverter, AthenaDistributedConverter
diff --git a/yt/utilities/grid_data_format/conversion/conversion_athena.py b/yt/utilities/grid_data_format/conversion/conversion_athena.py
index 52ef280786b..89ed9a3d6ce 100644
--- a/yt/utilities/grid_data_format/conversion/conversion_athena.py
+++ b/yt/utilities/grid_data_format/conversion/conversion_athena.py
@@ -1,7 +1,9 @@
+from glob import glob
+
 import numpy as np
+
 from yt.utilities.grid_data_format.conversion.conversion_abc import Converter
 from yt.utilities.on_demand_imports import _h5py as h5
-from glob import glob
 
 translation_dict = {}
 translation_dict['density'] = 'density'
@@ -481,4 +483,3 @@ def convert(self):
 #     fn = '%s.%04i'%(n[0],int(n[1]))
 #     grid = read_grid(fn+'.vtk')
 #     write_to_hdf5(fn+'.gdf',grid)
-    
diff --git a/yt/utilities/grid_data_format/scripts/convert_distributed_athena.py b/yt/utilities/grid_data_format/scripts/convert_distributed_athena.py
index d32f066dc3d..b7f084a3b73 100644
--- a/yt/utilities/grid_data_format/scripts/convert_distributed_athena.py
+++ b/yt/utilities/grid_data_format/scripts/convert_distributed_athena.py
@@ -1,5 +1,7 @@
-from grid_data_format import AthenaDistributedConverter
 import sys
+
+from grid_data_format import AthenaDistributedConverter
+
 # Assumes that last input is the basename for the athena dataset.
 # i.e. kh_3d_mhd_hlld_128_beta5000_sub_tanhd.0030
 basename = sys.argv[-1]
@@ -19,4 +21,3 @@
 
 # converter = AthenaDistributedConverter(basename, field_conversions=code_to_cgs)
 # converter.convert()
-
diff --git a/yt/utilities/grid_data_format/scripts/convert_single_athena.py b/yt/utilities/grid_data_format/scripts/convert_single_athena.py
index 7a9ca9609e4..0156b106020 100644
--- a/yt/utilities/grid_data_format/scripts/convert_single_athena.py
+++ b/yt/utilities/grid_data_format/scripts/convert_single_athena.py
@@ -1,5 +1,7 @@
-from grid_data_format import AthenaConverter
 import sys
+
+from grid_data_format import AthenaConverter
+
 # Assumes that last input is the basename for the athena dataset.
 # i.e. kh_3d_mhd_hlld_128_beta5000_sub_tanhd.0030
 basename = sys.argv[-1]
@@ -19,5 +21,3 @@
 
 # converter = AthenaDistributedConverter(basename, field_conversions=code_to_cgs)
 # converter.convert()
-
-
diff --git a/yt/utilities/grid_data_format/tests/test_writer.py b/yt/utilities/grid_data_format/tests/test_writer.py
index 2950e17906b..49a2e2f1654 100644
--- a/yt/utilities/grid_data_format/tests/test_writer.py
+++ b/yt/utilities/grid_data_format/tests/test_writer.py
@@ -1,17 +1,12 @@
-import tempfile
-import shutil
 import os
+import shutil
+import tempfile
+
+from yt.frontends.gdf.data_structures import GDFDataset
+from yt.mods import load
+from yt.testing import assert_equal, fake_random_ds, requires_module
+from yt.utilities.grid_data_format.writer import write_to_gdf
 from yt.utilities.on_demand_imports import _h5py as h5
-from yt.testing import \
-    fake_random_ds, \
-    assert_equal, \
-    requires_module
-from yt.utilities.grid_data_format.writer import \
-    write_to_gdf
-from yt.frontends.gdf.data_structures import \
-    GDFDataset
-from yt.mods import \
-    load
 
 TEST_AUTHOR = "yt test runner"
 TEST_COMMENT = "Testing write_to_gdf"
diff --git a/yt/utilities/grid_data_format/writer.py b/yt/utilities/grid_data_format/writer.py
index 309b463c4f5..73fd424c41d 100644
--- a/yt/utilities/grid_data_format/writer.py
+++ b/yt/utilities/grid_data_format/writer.py
@@ -1,15 +1,17 @@
 import os
 import sys
-from yt.utilities.on_demand_imports import _h5py as h5py
-import numpy as np
 from contextlib import contextmanager
 
+import numpy as np
+
 from yt import __version__ as yt_version
-from yt.utilities.exceptions import YTGDFAlreadyExists
 from yt.funcs import ensure_list, issue_deprecation_warning
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_objects, \
-    communication_system
+from yt.utilities.exceptions import YTGDFAlreadyExists
+from yt.utilities.on_demand_imports import _h5py as h5py
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    communication_system,
+    parallel_objects,
+)
 
 
 def write_to_gdf(ds, gdf_path, fields=None, 
diff --git a/yt/utilities/initial_conditions.py b/yt/utilities/initial_conditions.py
index 259e5b05100..a76ddd006b8 100644
--- a/yt/utilities/initial_conditions.py
+++ b/yt/utilities/initial_conditions.py
@@ -1,5 +1,6 @@
 import numpy as np
 
+
 class FluidOperator:
     def apply(self, ds):
         for g in ds.index.grids: self(g)
diff --git a/yt/utilities/io_handler.py b/yt/utilities/io_handler.py
index 420db5cc5bc..3214fa9f789 100644
--- a/yt/utilities/io_handler.py
+++ b/yt/utilities/io_handler.py
@@ -1,12 +1,12 @@
+import os
 from collections import defaultdict
 from contextlib import contextmanager
 
-import os
-from yt.utilities.on_demand_imports import _h5py as h5py
 import numpy as np
-from yt.utilities.lru_cache import \
-    local_lru_cache, _make_key
+
 from yt.geometry.selection_routines import GridSelector
+from yt.utilities.lru_cache import _make_key, local_lru_cache
+from yt.utilities.on_demand_imports import _h5py as h5py
 
 io_registry = {}
 
diff --git a/yt/utilities/lib/api.py b/yt/utilities/lib/api.py
index ea60c087c08..19b2bd368a8 100644
--- a/yt/utilities/lib/api.py
+++ b/yt/utilities/lib/api.py
@@ -1,15 +1,15 @@
-from .grid_traversal import *
-from .particle_mesh_operations import *
+from .basic_octree import *
+from .contour_finding import *
 from .depth_first_octree import *
 from .fortran_reader import *
+from .grid_traversal import *
+from .image_utilities import *
 from .interpolators import *
+from .line_integral_convolution import *
+from .marching_cubes import *
+from .mesh_utilities import *
 from .misc_utilities import *
-from .basic_octree import *
-from .image_utilities import *
+from .particle_mesh_operations import *
 from .points_in_volume import *
 from .quad_tree import *
-from .marching_cubes import *
 from .write_array import *
-from .mesh_utilities import *
-from .contour_finding import *
-from .line_integral_convolution import *
diff --git a/yt/utilities/lib/cykdtree/__init__.py b/yt/utilities/lib/cykdtree/__init__.py
index 675daffbbfb..2c9c9bc245a 100644
--- a/yt/utilities/lib/cykdtree/__init__.py
+++ b/yt/utilities/lib/cykdtree/__init__.py
@@ -1,5 +1,6 @@
-from yt.utilities.lib.cykdtree.kdtree import PyKDTree, PyNode  # NOQA
 from yt.utilities.lib.cykdtree import plot  # NOQA
+from yt.utilities.lib.cykdtree.kdtree import PyKDTree, PyNode  # NOQA
+
 
 def make_tree(pts, **kwargs):
     r"""Build a KD-tree for a set of points.
diff --git a/yt/utilities/lib/cykdtree/plot.py b/yt/utilities/lib/cykdtree/plot.py
index 069b8b31b14..5bd5cf40835 100644
--- a/yt/utilities/lib/cykdtree/plot.py
+++ b/yt/utilities/lib/cykdtree/plot.py
@@ -1,5 +1,6 @@
 import numpy as np
 
+
 def _plot2D_root(seg, pts=None, txt=None, plotfile=None, point_kw={}, box_kw={},
                  axs=None, subplot_kw={}, gridspec_kw={}, fig_kw={}, 
                  save_kw={}, title=None, xlabel='x', ylabel='y', label_kw={}):
diff --git a/yt/utilities/lib/cykdtree/tests/__init__.py b/yt/utilities/lib/cykdtree/tests/__init__.py
index 450a1912a45..8a048d5e231 100644
--- a/yt/utilities/lib/cykdtree/tests/__init__.py
+++ b/yt/utilities/lib/cykdtree/tests/__init__.py
@@ -1,12 +1,13 @@
-from datetime import datetime
 import cProfile
+import itertools
 import pstats
+import sys
 import time
-from subprocess import Popen, PIPE
-from nose.tools import nottest
+from datetime import datetime
+from subprocess import PIPE, Popen
+
 import numpy as np
-import itertools
-import sys
+from nose.tools import nottest
 
 
 def assert_less_equal(x, y):
diff --git a/yt/utilities/lib/cykdtree/tests/scaling.py b/yt/utilities/lib/cykdtree/tests/scaling.py
index 0213c0cf74e..d5d1881edb3 100644
--- a/yt/utilities/lib/cykdtree/tests/scaling.py
+++ b/yt/utilities/lib/cykdtree/tests/scaling.py
@@ -1,9 +1,11 @@
 r"""Routines for tracking the scaling of the triangulation routines."""
-import numpy as np
-import time
-import os
 import cProfile
+import os
 import pstats
+import time
+
+import numpy as np
+
 from yt.utilities.lib.cykdtree.tests import run_test
 
 
diff --git a/yt/utilities/lib/cykdtree/tests/test_kdtree.py b/yt/utilities/lib/cykdtree/tests/test_kdtree.py
index 9a0445578f2..b397315934c 100644
--- a/yt/utilities/lib/cykdtree/tests/test_kdtree.py
+++ b/yt/utilities/lib/cykdtree/tests/test_kdtree.py
@@ -1,12 +1,14 @@
-import numpy as np
-import time
 import tempfile
+import time
+
+import numpy as np
 from nose.tools import assert_raises
+
 import yt.utilities.lib.cykdtree as cykdtree
 from yt.utilities.lib.cykdtree.tests import (
-    parametrize,
     make_points,
     make_points_neighbors,
+    parametrize,
 )
 
 
diff --git a/yt/utilities/lib/cykdtree/tests/test_plot.py b/yt/utilities/lib/cykdtree/tests/test_plot.py
index 29e7f6b8e39..4fed890023a 100644
--- a/yt/utilities/lib/cykdtree/tests/test_plot.py
+++ b/yt/utilities/lib/cykdtree/tests/test_plot.py
@@ -1,6 +1,7 @@
 import os
-from yt.utilities.lib.cykdtree.plot import plot2D_serial
+
 from yt.utilities.lib.cykdtree.kdtree import PyKDTree
+from yt.utilities.lib.cykdtree.plot import plot2D_serial
 from yt.utilities.lib.cykdtree.tests import make_points
 
 
diff --git a/yt/utilities/lib/cykdtree/tests/test_utils.py b/yt/utilities/lib/cykdtree/tests/test_utils.py
index 91f0f173d2f..23c99b200c9 100644
--- a/yt/utilities/lib/cykdtree/tests/test_utils.py
+++ b/yt/utilities/lib/cykdtree/tests/test_utils.py
@@ -1,7 +1,9 @@
 import numpy as np
 from nose.tools import assert_equal
-from yt.utilities.lib.cykdtree.tests import parametrize, assert_less_equal
+
 from yt.utilities.lib.cykdtree import utils
+from yt.utilities.lib.cykdtree.tests import assert_less_equal, parametrize
+
 
 def test_max_pts():
     pts = np.arange(5*3).reshape((5, 3)).astype('float64')
diff --git a/yt/utilities/lib/tests/test_allocation_container.py b/yt/utilities/lib/tests/test_allocation_container.py
index bcf52b068b0..51ed93ceb4c 100644
--- a/yt/utilities/lib/tests/test_allocation_container.py
+++ b/yt/utilities/lib/tests/test_allocation_container.py
@@ -1,7 +1,6 @@
-from yt.testing import \
-    assert_array_equal, assert_equal
-from yt.utilities.lib.allocation_container import \
-    BitmaskPool
+from yt.testing import assert_array_equal, assert_equal
+from yt.utilities.lib.allocation_container import BitmaskPool
+
 
 def test_bitmask_pool():
     bmp = BitmaskPool()
diff --git a/yt/utilities/lib/tests/test_alt_ray_tracers.py b/yt/utilities/lib/tests/test_alt_ray_tracers.py
index ef7a9882c93..5b9dfd16d0f 100644
--- a/yt/utilities/lib/tests/test_alt_ray_tracers.py
+++ b/yt/utilities/lib/tests/test_alt_ray_tracers.py
@@ -1,13 +1,8 @@
 """Tests for non-cartesian ray tracers."""
 import numpy as np
 
-from yt.testing import \
-    assert_true, \
-    amrspace, \
-    assert_less_equal, \
-    assert_equal
-
-from yt.utilities.lib.alt_ray_tracers import cylindrical_ray_trace, _cyl2cart
+from yt.testing import amrspace, assert_equal, assert_less_equal, assert_true
+from yt.utilities.lib.alt_ray_tracers import _cyl2cart, cylindrical_ray_trace
 
 left_grid = right_grid = amr_levels = center_grid = data = None
 
diff --git a/yt/utilities/lib/tests/test_bitarray.py b/yt/utilities/lib/tests/test_bitarray.py
index 067ebeb1c7b..39dedfb0feb 100644
--- a/yt/utilities/lib/tests/test_bitarray.py
+++ b/yt/utilities/lib/tests/test_bitarray.py
@@ -1,7 +1,8 @@
 import numpy as np
 
 import yt.utilities.lib.bitarray as ba
-from yt.testing import assert_equal, assert_array_equal
+from yt.testing import assert_array_equal, assert_equal
+
 
 def test_inout_bitarray():
     # Check that we can do it for bitarrays that are funny-shaped
diff --git a/yt/utilities/lib/tests/test_bounding_volume_hierarchy.py b/yt/utilities/lib/tests/test_bounding_volume_hierarchy.py
index be3e4770dbc..436fee8957b 100644
--- a/yt/utilities/lib/tests/test_bounding_volume_hierarchy.py
+++ b/yt/utilities/lib/tests/test_bounding_volume_hierarchy.py
@@ -1,9 +1,9 @@
-import yt
 import numpy as np
-from yt.utilities.lib.bounding_volume_hierarchy import BVH, \
-    test_ray_trace
-from yt.visualization.volume_rendering.api import Camera, Scene
+
+import yt
 from yt.testing import requires_file
+from yt.utilities.lib.bounding_volume_hierarchy import BVH, test_ray_trace
+from yt.visualization.volume_rendering.api import Camera, Scene
 
 
 def get_rays(camera):
diff --git a/yt/utilities/lib/tests/test_element_mappings.py b/yt/utilities/lib/tests/test_element_mappings.py
index 55b583e7d44..7e0e6fedda8 100644
--- a/yt/utilities/lib/tests/test_element_mappings.py
+++ b/yt/utilities/lib/tests/test_element_mappings.py
@@ -1,17 +1,19 @@
 
 import numpy as np
+
 from yt.testing import assert_almost_equal
-from yt.utilities.lib.element_mappings import \
-    test_tetra_sampler, \
-    test_hex_sampler, \
-    test_tri_sampler, \
-    test_quad_sampler, \
-    test_quad2_sampler, \
-    test_hex20_sampler, \
-    test_wedge_sampler, \
-    test_tri2_sampler, \
-    test_tet2_sampler, \
-    test_linear1D_sampler
+from yt.utilities.lib.element_mappings import (
+    test_hex20_sampler,
+    test_hex_sampler,
+    test_linear1D_sampler,
+    test_quad2_sampler,
+    test_quad_sampler,
+    test_tet2_sampler,
+    test_tetra_sampler,
+    test_tri2_sampler,
+    test_tri_sampler,
+    test_wedge_sampler,
+)
 
 
 def check_all_vertices(sampler, vertices, field_values):
diff --git a/yt/utilities/lib/tests/test_fill_region.py b/yt/utilities/lib/tests/test_fill_region.py
index 4a5ac8095dc..d42f598b8c3 100644
--- a/yt/utilities/lib/tests/test_fill_region.py
+++ b/yt/utilities/lib/tests/test_fill_region.py
@@ -30,4 +30,3 @@ def test_fill_region():
         for r in range(level + 1):
             for o, i in zip(output_fields, v):
                 assert_equal( o[r::rf,r::rf,r::rf], i)
-
diff --git a/yt/utilities/lib/tests/test_geometry_utils.py b/yt/utilities/lib/tests/test_geometry_utils.py
index e9cec61f348..b97f53762f6 100644
--- a/yt/utilities/lib/tests/test_geometry_utils.py
+++ b/yt/utilities/lib/tests/test_geometry_utils.py
@@ -1,14 +1,16 @@
 import numpy as np
 
-from yt.testing import \
-    fake_random_ds, \
-    assert_array_equal, \
-    assert_array_less, \
-    assert_equal, \
-    assert_raises
-from yt.utilities.lib.misc_utilities import \
-    obtain_position_vector, \
-    obtain_relative_velocity_vector
+from yt.testing import (
+    assert_array_equal,
+    assert_array_less,
+    assert_equal,
+    assert_raises,
+    fake_random_ds,
+)
+from yt.utilities.lib.misc_utilities import (
+    obtain_position_vector,
+    obtain_relative_velocity_vector,
+)
 
 _fields = ("density", "velocity_x", "velocity_y", "velocity_z")
 
diff --git a/yt/utilities/lib/tests/test_nn.py b/yt/utilities/lib/tests/test_nn.py
index 5c0b0833e0a..6165f6fee43 100644
--- a/yt/utilities/lib/tests/test_nn.py
+++ b/yt/utilities/lib/tests/test_nn.py
@@ -1,11 +1,12 @@
 import numpy as np
 
-from yt.utilities.lib.bounded_priority_queue import \
-    validate, \
-    validate_pid, \
-    validate_nblist
-
 from yt.testing import assert_array_equal
+from yt.utilities.lib.bounded_priority_queue import (
+    validate,
+    validate_nblist,
+    validate_pid,
+)
+
 
 # These test functions use utility functions in
 # yt.utilities.lib.bounded_priority_queue
diff --git a/yt/utilities/lib/tests/test_ragged_arrays.py b/yt/utilities/lib/tests/test_ragged_arrays.py
index 0e263fe373b..810dc5d8266 100644
--- a/yt/utilities/lib/tests/test_ragged_arrays.py
+++ b/yt/utilities/lib/tests/test_ragged_arrays.py
@@ -1,10 +1,7 @@
 import numpy as np
 
+from yt.testing import assert_equal, assert_rel_equal
 from yt.utilities.lib.ragged_arrays import index_unop
-from yt.testing import \
-    assert_equal, \
-    assert_rel_equal
-
 
 operations = ((np.sum, "sum"),
               (np.prod, "prod"),
diff --git a/yt/utilities/lib/tests/test_sample.py b/yt/utilities/lib/tests/test_sample.py
index c871936519b..a21bc1b81ee 100644
--- a/yt/utilities/lib/tests/test_sample.py
+++ b/yt/utilities/lib/tests/test_sample.py
@@ -1,8 +1,8 @@
 import numpy as np
 
-from yt.utilities.lib.particle_mesh_operations import \
-    CICSample_3
 from yt.testing import assert_allclose
+from yt.utilities.lib.particle_mesh_operations import CICSample_3
+
 
 def setup():
     pass
diff --git a/yt/utilities/linear_interpolators.py b/yt/utilities/linear_interpolators.py
index edc54faeead..a6f7633c861 100644
--- a/yt/utilities/linear_interpolators.py
+++ b/yt/utilities/linear_interpolators.py
@@ -1,7 +1,8 @@
 import numpy as np
 
-from yt.funcs import mylog
 import yt.utilities.lib.interpolators as lib
+from yt.funcs import mylog
+
 
 class UnilinearFieldInterpolator:
     def __init__(self, table, boundaries, field_names, truncate=False):
diff --git a/yt/utilities/load_sample.py b/yt/utilities/load_sample.py
index 23c0c79871d..b09f87e7fea 100644
--- a/yt/utilities/load_sample.py
+++ b/yt/utilities/load_sample.py
@@ -6,11 +6,13 @@
 
 """
 import os
+
 import yt.utilities.sample_data as sd
-from yt.funcs import mylog
 from yt.convenience import load
+from yt.funcs import mylog
 from yt.utilities.on_demand_imports import _pooch as pch
 
+
 def load_sample(name=None, specific_file=None, pbar=True):
     """
     Load sample data with yt. Simple wrapper around yt.load to include fetching
diff --git a/yt/utilities/lodgeit.py b/yt/utilities/lodgeit.py
index 5c6ac6b7b06..4c56f5deb6b 100644
--- a/yt/utilities/lodgeit.py
+++ b/yt/utilities/lodgeit.py
@@ -30,6 +30,7 @@
 import os
 import sys
 from optparse import OptionParser
+
 if sys.version_info >= (3,0,0):
     unicode = str
 
diff --git a/yt/utilities/logger.py b/yt/utilities/logger.py
index ad2aaf3395f..846884f5651 100644
--- a/yt/utilities/logger.py
+++ b/yt/utilities/logger.py
@@ -1,5 +1,6 @@
 import logging
 import sys
+
 from yt.config import ytcfg
 
 # This next bit is grabbed from:
diff --git a/yt/utilities/lru_cache.py b/yt/utilities/lru_cache.py
index a2bb1e599e6..4106ee4c0ef 100644
--- a/yt/utilities/lru_cache.py
+++ b/yt/utilities/lru_cache.py
@@ -1,5 +1,4 @@
 import sys
-
 from collections import namedtuple
 from functools import update_wrapper
 from threading import RLock
diff --git a/yt/utilities/math_utils.py b/yt/utilities/math_utils.py
index b8867a6fc2e..129771803e3 100644
--- a/yt/utilities/math_utils.py
+++ b/yt/utilities/math_utils.py
@@ -1,7 +1,8 @@
-import numpy as np
 import math
-from yt.units.yt_array import \
-    YTArray
+
+import numpy as np
+
+from yt.units.yt_array import YTArray
 
 prec_accum = {
     np.int:                 np.int64,
diff --git a/yt/utilities/mesh_code_generation.py b/yt/utilities/mesh_code_generation.py
index e51fdc99356..8ae25ac9fe9 100644
--- a/yt/utilities/mesh_code_generation.py
+++ b/yt/utilities/mesh_code_generation.py
@@ -1,11 +1,5 @@
-from sympy import \
-    symarray, \
-    diff, \
-    ccode, \
-    Matrix, \
-    MatrixSymbol
 import yaml
-
+from sympy import Matrix, MatrixSymbol, ccode, diff, symarray
 
 # define some templates used below
 fun_signature = '''cdef void %s(double* fx,
diff --git a/yt/utilities/minimal_representation.py b/yt/utilities/minimal_representation.py
index cffcbeffc87..14820568ae2 100644
--- a/yt/utilities/minimal_representation.py
+++ b/yt/utilities/minimal_representation.py
@@ -1,22 +1,20 @@
-import numpy as np
 import abc
 import json
-import sys
-from yt.utilities.on_demand_imports import _h5py as h5
 import os
-from uuid import uuid4
-import urllib
 import pickle
+import sys
+import urllib
 from tempfile import TemporaryFile
+from uuid import uuid4
+
+import numpy as np
+
 from yt.config import ytcfg
-from yt.funcs import \
-    iterable, get_pbar, compare_dicts
-from yt.utilities.exceptions import \
-    YTHubRegisterError
+from yt.funcs import compare_dicts, get_pbar, iterable
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.exceptions import YTHubRegisterError
 from yt.utilities.logger import ytLogger as mylog
-from yt.units.yt_array import \
-    YTArray, \
-    YTQuantity
+from yt.utilities.on_demand_imports import _h5py as h5
 
 if sys.version_info < (3, 0):
     from .poster.streaminghttp import register_openers
diff --git a/yt/utilities/nodal_data_utils.py b/yt/utilities/nodal_data_utils.py
index eeec6310743..d7506953a5e 100644
--- a/yt/utilities/nodal_data_utils.py
+++ b/yt/utilities/nodal_data_utils.py
@@ -1,4 +1,4 @@
-import numpy as np    
+import numpy as np
 
 _index_map = np.array([[0, 0, 0, 0, 0, 0, 0, 0],
                       [0, 1, 0, 1, 0, 1, 0, 1],
diff --git a/yt/utilities/on_demand_imports.py b/yt/utilities/on_demand_imports.py
index 47360584b3f..08234e9c3c3 100644
--- a/yt/utilities/on_demand_imports.py
+++ b/yt/utilities/on_demand_imports.py
@@ -1,6 +1,8 @@
-from pkg_resources import parse_version
 import sys
 
+from pkg_resources import parse_version
+
+
 class NotAModule:
     """
     A class to implement an informative error message that will be outputted if
diff --git a/yt/utilities/operator_registry.py b/yt/utilities/operator_registry.py
index c262a7eb835..f60027e488a 100644
--- a/yt/utilities/operator_registry.py
+++ b/yt/utilities/operator_registry.py
@@ -1,5 +1,6 @@
 import copy
 
+
 class OperatorRegistry(dict):
     def find(self, op, *args, **kwargs):
         if isinstance(op, str):
diff --git a/yt/utilities/orientation.py b/yt/utilities/orientation.py
index 62893ee3e91..f5798262379 100644
--- a/yt/utilities/orientation.py
+++ b/yt/utilities/orientation.py
@@ -4,6 +4,7 @@
 from yt.units.yt_array import YTArray
 from yt.utilities.exceptions import YTException
 
+
 def _aligned(a, b):
     aligned_component = np.abs(np.dot(a, b) / np.linalg.norm(a) / np.linalg.norm(b))
     return np.isclose(aligned_component, 1.0, 1.0e-13)
diff --git a/yt/utilities/parallel_tools/__init__.py b/yt/utilities/parallel_tools/__init__.py
index ad451d69e99..4a3abab14ea 100644
--- a/yt/utilities/parallel_tools/__init__.py
+++ b/yt/utilities/parallel_tools/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/utilities/parallel_tools/controller_system.py b/yt/utilities/parallel_tools/controller_system.py
index 9db54044611..a937a2f093a 100644
--- a/yt/utilities/parallel_tools/controller_system.py
+++ b/yt/utilities/parallel_tools/controller_system.py
@@ -1,7 +1,8 @@
-from .parallel_analysis_interface import \
-    ProcessorPool
 from abc import abstractmethod
 
+from .parallel_analysis_interface import ProcessorPool
+
+
 class WorkSplitter:
     def __init__(self, controller, group1, group2):
         self.group1 = group1
diff --git a/yt/utilities/parallel_tools/io_runner.py b/yt/utilities/parallel_tools/io_runner.py
index e67568be1a7..c25e3e5084d 100644
--- a/yt/utilities/parallel_tools/io_runner.py
+++ b/yt/utilities/parallel_tools/io_runner.py
@@ -1,10 +1,12 @@
+import time
+from contextlib import contextmanager
+
 import numpy as np
-from yt.utilities.logger import ytLogger as mylog
-from .parallel_analysis_interface import \
-    ProcessorPool, parallel_objects
+
 from yt.utilities.io_handler import BaseIOHandler
-from contextlib import contextmanager
-import time
+from yt.utilities.logger import ytLogger as mylog
+
+from .parallel_analysis_interface import ProcessorPool, parallel_objects
 
 try:
     from .parallel_analysis_interface import MPI
@@ -169,5 +171,3 @@ def gq(ds):
         return dd.quantities["TotalQuantity"]("CellMassMsun")
     q = io_nodes("DD0087/DD0087", 8, 24, gq)
     mylog.info(q)
-
-
diff --git a/yt/utilities/parallel_tools/parallel_analysis_interface.py b/yt/utilities/parallel_tools/parallel_analysis_interface.py
index 61178d0b8f8..9b609ced29d 100644
--- a/yt/utilities/parallel_tools/parallel_analysis_interface.py
+++ b/yt/utilities/parallel_tools/parallel_analysis_interface.py
@@ -1,23 +1,21 @@
-from io import StringIO
 import itertools
 import logging
-import numpy as np
-import sys
 import os
+import sys
 import traceback
 from functools import wraps
+from io import StringIO
 
-from yt.funcs import \
-    ensure_list, iterable
+import numpy as np
 
+import yt.utilities.logger
 from yt.config import ytcfg
 from yt.data_objects.image_array import ImageArray
-import yt.utilities.logger
-from yt.utilities.lib.quad_tree import \
-    QuadTree, merge_quadtrees
-from yt.units.yt_array import YTArray
+from yt.funcs import ensure_list, iterable
 from yt.units.unit_registry import UnitRegistry
+from yt.units.yt_array import YTArray
 from yt.utilities.exceptions import YTNoDataInObjectError
+from yt.utilities.lib.quad_tree import QuadTree, merge_quadtrees
 from yt.utilities.logger import ytLogger as mylog
 
 # We default to *no* parallelism unless it gets turned on, in which case this
diff --git a/yt/utilities/parallel_tools/task_queue.py b/yt/utilities/parallel_tools/task_queue.py
index 0c8260814a5..8b580f636bc 100644
--- a/yt/utilities/parallel_tools/task_queue.py
+++ b/yt/utilities/parallel_tools/task_queue.py
@@ -1,11 +1,13 @@
 import numpy as np
 
 from yt.funcs import mylog
-from .parallel_analysis_interface import \
-    communication_system, \
-    _get_comm, \
-    parallel_capable, \
-    ResultsStorage
+
+from .parallel_analysis_interface import (
+    ResultsStorage,
+    _get_comm,
+    communication_system,
+    parallel_capable,
+)
 
 messages = dict(
     task = dict(msg = 'next'),
diff --git a/yt/utilities/parameter_file_storage.py b/yt/utilities/parameter_file_storage.py
index 616fe495b7d..34ca70d5bf2 100644
--- a/yt/utilities/parameter_file_storage.py
+++ b/yt/utilities/parameter_file_storage.py
@@ -3,10 +3,10 @@
 from itertools import islice
 
 from yt.config import ytcfg
-from yt.funcs import \
-    mylog
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_simple_proxy
+from yt.funcs import mylog
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    parallel_simple_proxy,
+)
 
 output_type_registry = {}
 simulation_time_series_registry = {}
diff --git a/yt/utilities/particle_generator.py b/yt/utilities/particle_generator.py
index 7e407c73137..07fdaf46c4a 100644
--- a/yt/utilities/particle_generator.py
+++ b/yt/utilities/particle_generator.py
@@ -1,8 +1,9 @@
 import numpy as np
-from yt.utilities.lib.particle_mesh_operations import \
-    CICSample_3
+
 from yt.funcs import get_pbar, issue_deprecation_warning
 from yt.units.yt_array import uconcatenate
+from yt.utilities.lib.particle_mesh_operations import CICSample_3
+
 
 class ParticleGenerator:
 
@@ -409,4 +410,3 @@ def __init__(self, ds, data_source, num_particles, field_list,
         z = uconcatenate(all_z)
 
         self._setup_particles(x, y, z)
-
diff --git a/yt/utilities/performance_counters.py b/yt/utilities/performance_counters.py
index 86ded71c5d5..538bbaf42ad 100644
--- a/yt/utilities/performance_counters.py
+++ b/yt/utilities/performance_counters.py
@@ -1,6 +1,5 @@
 import atexit
 import time
-
 from bisect import insort
 from collections import defaultdict
 from datetime import datetime as dt
@@ -9,6 +8,7 @@
 from yt.config import ytcfg
 from yt.funcs import mylog
 
+
 class PerformanceCounters:
     _shared_state = {}
     def __new__(cls, *args, **kwargs):
diff --git a/yt/utilities/periodic_table.py b/yt/utilities/periodic_table.py
index b25a6395cc0..3d1ebeab4dd 100644
--- a/yt/utilities/periodic_table.py
+++ b/yt/utilities/periodic_table.py
@@ -1,6 +1,7 @@
-import numpy as np
 import numbers
 
+import numpy as np
+
 _elements = (
     (1, 1.0079400000, "Hydrogen", "H"),
     (2, 4.0026020000, "Helium", "He"),
diff --git a/yt/utilities/physical_constants.py b/yt/utilities/physical_constants.py
index aaa0cbdfaa3..a6fcb5c0fb7 100644
--- a/yt/utilities/physical_constants.py
+++ b/yt/utilities/physical_constants.py
@@ -1,30 +1,31 @@
 from math import pi
 
-from yt.utilities.physical_ratios import \
-    mass_electron_grams, \
-    amu_grams, \
-    mass_hydrogen_grams, \
-    speed_of_light_cm_per_s, \
-    boltzmann_constant_erg_per_K, \
-    mass_sun_grams, \
-    mass_jupiter_grams, \
-    mass_mercury_grams, \
-    mass_venus_grams, \
-    mass_earth_grams, \
-    mass_mars_grams, \
-    mass_saturn_grams, \
-    mass_uranus_grams, \
-    mass_neptune_grams, \
-    planck_mass_grams, \
-    planck_length_cm, \
-    planck_time_s, \
-    planck_energy_erg, \
-    planck_charge_esu, \
-    planck_temperature_K, \
-    standard_gravity_cm_per_s2, \
-    newton_cgs, \
-    planck_cgs
 from yt.units.yt_array import YTQuantity
+from yt.utilities.physical_ratios import (
+    amu_grams,
+    boltzmann_constant_erg_per_K,
+    mass_earth_grams,
+    mass_electron_grams,
+    mass_hydrogen_grams,
+    mass_jupiter_grams,
+    mass_mars_grams,
+    mass_mercury_grams,
+    mass_neptune_grams,
+    mass_saturn_grams,
+    mass_sun_grams,
+    mass_uranus_grams,
+    mass_venus_grams,
+    newton_cgs,
+    planck_cgs,
+    planck_charge_esu,
+    planck_energy_erg,
+    planck_length_cm,
+    planck_mass_grams,
+    planck_temperature_K,
+    planck_time_s,
+    speed_of_light_cm_per_s,
+    standard_gravity_cm_per_s2,
+)
 
 mass_electron_cgs = YTQuantity(mass_electron_grams, 'g')
 mass_electron = mass_electron_cgs
@@ -137,4 +138,3 @@
 # Misc
 standard_gravity_cgs = YTQuantity(standard_gravity_cm_per_s2, "cm/s**2")
 standard_gravity = standard_gravity_cgs
-
diff --git a/yt/utilities/physical_ratios.py b/yt/utilities/physical_ratios.py
index ee446c07fd9..976e95d5d5d 100644
--- a/yt/utilities/physical_ratios.py
+++ b/yt/utilities/physical_ratios.py
@@ -1,4 +1,5 @@
 import numpy as np
+
 #
 # Physical Constants and Units Conversion Factors
 #
diff --git a/yt/utilities/png_writer.py b/yt/utilities/png_writer.py
index 8513a28e35f..836ae5beb03 100644
--- a/yt/utilities/png_writer.py
+++ b/yt/utilities/png_writer.py
@@ -1,6 +1,7 @@
+from io import BytesIO
+
 import matplotlib._png as _png
 
-from io import BytesIO
 
 def call_png_write_png(buffer, width, height, fileobj, dpi):
     _png.write_png(buffer, fileobj, dpi)
diff --git a/yt/utilities/poster/__init__.py b/yt/utilities/poster/__init__.py
index 7748064e3e4..d01b5de2a29 100644
--- a/yt/utilities/poster/__init__.py
+++ b/yt/utilities/poster/__init__.py
@@ -27,7 +27,6 @@
 New in version 0.6."""
 
 
-from . import streaminghttp
-from . import encode
+from . import encode, streaminghttp
 
 version = (0, 8, 1) # Thanks JP!
diff --git a/yt/utilities/poster/encode.py b/yt/utilities/poster/encode.py
index 4c47fcb5c52..159945ab755 100644
--- a/yt/utilities/poster/encode.py
+++ b/yt/utilities/poster/encode.py
@@ -21,8 +21,11 @@ def gen_boundary():
         bits = random.getrandbits(160)
         return sha.new(str(bits)).hexdigest()
 
-import re, os, mimetypes
+import mimetypes
+import os
+import re
 import urllib
+
 try:
     from email.header import Header
 except ImportError:
diff --git a/yt/utilities/poster/streaminghttp.py b/yt/utilities/poster/streaminghttp.py
index 21571c1dbf8..0f5920406e0 100644
--- a/yt/utilities/poster/streaminghttp.py
+++ b/yt/utilities/poster/streaminghttp.py
@@ -28,9 +28,10 @@
 
 
 import http.client as http_client
-import urllib
 import socket
 import sys
+import urllib
+
 
 def request_has_data(req):
     if sys.version_info >= (3,0,0):
diff --git a/yt/utilities/rpdb.py b/yt/utilities/rpdb.py
index 50a534c03d2..8e72f668f75 100644
--- a/yt/utilities/rpdb.py
+++ b/yt/utilities/rpdb.py
@@ -1,14 +1,16 @@
 import cmd
 import pdb
+import signal
 import socket
 import sys
-from io import StringIO
 import traceback
-import signal
-from xmlrpc.server import SimpleXMLRPCServer
+from io import StringIO
 from xmlrpc.client import ServerProxy
+from xmlrpc.server import SimpleXMLRPCServer
+
 from yt.config import ytcfg
 
+
 class PdbXMLRPCServer(SimpleXMLRPCServer):
     """
     shutdown-enabled XMLRPCServer from
diff --git a/yt/utilities/sample_data.py b/yt/utilities/sample_data.py
index ac6da707669..3b567f84c0e 100644
--- a/yt/utilities/sample_data.py
+++ b/yt/utilities/sample_data.py
@@ -3,13 +3,13 @@
 Purpose: Contains functions used for automatic downloading and loading
             of sample data that is not already present locally.
 """
-import pkg_resources
 import json
 import os
 
-from yt.utilities.on_demand_imports import _pooch as pch
+import pkg_resources
 
 from yt.config import ytcfg
+from yt.utilities.on_demand_imports import _pooch as pch
 
 ## The format of the data registry json:
 ##
diff --git a/yt/utilities/sdf.py b/yt/utilities/sdf.py
index 8b20a972b17..39cbf29be8b 100644
--- a/yt/utilities/sdf.py
+++ b/yt/utilities/sdf.py
@@ -1,9 +1,11 @@
-from io import StringIO
 import os
+from io import StringIO
+
 import numpy as np
 
 from yt.funcs import mylog
 
+
 def get_thingking_deps():
     try:
         from thingking.httpmmap import HTTPArray
diff --git a/yt/utilities/tests/test_amr_kdtree.py b/yt/utilities/tests/test_amr_kdtree.py
index 88d3ed45fda..883752d3b3f 100644
--- a/yt/utilities/tests/test_amr_kdtree.py
+++ b/yt/utilities/tests/test_amr_kdtree.py
@@ -1,10 +1,12 @@
-from yt.utilities.amr_kdtree.api import AMRKDTree
-import yt.utilities.initial_conditions as ic
+import itertools
+
+import numpy as np
+
 import yt.utilities.flagging_methods as fm
+import yt.utilities.initial_conditions as ic
 from yt.frontends.stream.api import load_uniform_grid, refine_amr
-from yt.testing import assert_equal, assert_almost_equal, fake_amr_ds
-import numpy as np
-import itertools
+from yt.testing import assert_almost_equal, assert_equal, fake_amr_ds
+from yt.utilities.amr_kdtree.api import AMRKDTree
 
 
 def test_amr_kdtree_coverage():
diff --git a/yt/utilities/tests/test_chemical_formulas.py b/yt/utilities/tests/test_chemical_formulas.py
index 8dd00526d22..9cb68d0baae 100644
--- a/yt/utilities/tests/test_chemical_formulas.py
+++ b/yt/utilities/tests/test_chemical_formulas.py
@@ -1,4 +1,4 @@
-from yt.testing import assert_equal, assert_allclose
+from yt.testing import assert_allclose, assert_equal
 from yt.utilities.chemical_formulas import ChemicalFormula, default_mu
 from yt.utilities.periodic_table import periodic_table
 
diff --git a/yt/utilities/tests/test_config.py b/yt/utilities/tests/test_config.py
index 5caecd684b2..f8bcda43f72 100644
--- a/yt/utilities/tests/test_config.py
+++ b/yt/utilities/tests/test_config.py
@@ -1,6 +1,15 @@
 import contextlib
 import os
 import sys
+import unittest
+from configparser import NoOptionError
+from io import StringIO
+
+import yt.config
+import yt.utilities.command_line
+from yt.config import _OLD_CONFIG_FILE, CONFIG_DIR, CURRENT_CONFIG_FILE, YTConfigParser
+from yt.fields.tests.test_fields_plugins import TEST_PLUGIN_FILE
+
 if sys.version_info.major < 3:
     try:
         import mock
@@ -8,14 +17,6 @@
         mock = None
 else:
     import unittest.mock as mock
-import unittest
-import yt.utilities.command_line
-import yt.config
-from yt.config import \
-    CURRENT_CONFIG_FILE, _OLD_CONFIG_FILE, CONFIG_DIR, YTConfigParser
-from io import StringIO
-from configparser import NoOptionError
-from yt.fields.tests.test_fields_plugins import TEST_PLUGIN_FILE
 
 _TEST_PLUGIN = '_test_plugin.py'
 _DUMMY_CFG = ['[yt]', 'loglevel = 49', 'pluginfilename = ' + _TEST_PLUGIN]
diff --git a/yt/utilities/tests/test_coordinate_conversions.py b/yt/utilities/tests/test_coordinate_conversions.py
index a90571507fe..9f244e36a47 100644
--- a/yt/utilities/tests/test_coordinate_conversions.py
+++ b/yt/utilities/tests/test_coordinate_conversions.py
@@ -1,16 +1,20 @@
 import numpy as np
 
 from yt.testing import assert_array_almost_equal
-from yt.utilities.math_utils import \
-    get_sph_r_component, \
-    get_sph_theta_component, \
-    get_sph_phi_component, \
-    get_cyl_r_component, \
-    get_cyl_z_component, \
-    get_cyl_theta_component, \
-    get_cyl_r, get_cyl_theta, \
-    get_cyl_z, get_sph_r, \
-    get_sph_theta, get_sph_phi
+from yt.utilities.math_utils import (
+    get_cyl_r,
+    get_cyl_r_component,
+    get_cyl_theta,
+    get_cyl_theta_component,
+    get_cyl_z,
+    get_cyl_z_component,
+    get_sph_phi,
+    get_sph_phi_component,
+    get_sph_r,
+    get_sph_r_component,
+    get_sph_theta,
+    get_sph_theta_component,
+)
 
 # Randomly generated coordinates in the domain [[-1,1],[-1,1],-1,1]]
 coords = np.array([[-0.41503037, -0.22102472, -0.55774212],
diff --git a/yt/utilities/tests/test_cosmology.py b/yt/utilities/tests/test_cosmology.py
index 224d7500485..b8c69b513ad 100644
--- a/yt/utilities/tests/test_cosmology.py
+++ b/yt/utilities/tests/test_cosmology.py
@@ -1,20 +1,18 @@
-import numpy as np
 import os
-from yt.utilities.on_demand_imports import \
-    _yaml as yaml
-from yt.testing import \
-     assert_almost_equal, \
-     assert_rel_equal, \
-     assert_equal, \
-     requires_file, \
-     requires_module
-from yt.units.yt_array import \
-     YTArray, \
-     YTQuantity
-from yt.utilities.answer_testing.framework import \
-     data_dir_load
-from yt.utilities.cosmology import \
-     Cosmology
+
+import numpy as np
+
+from yt.testing import (
+    assert_almost_equal,
+    assert_equal,
+    assert_rel_equal,
+    requires_file,
+    requires_module,
+)
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.answer_testing.framework import data_dir_load
+from yt.utilities.cosmology import Cosmology
+from yt.utilities.on_demand_imports import _yaml as yaml
 
 local_dir = os.path.dirname(os.path.abspath(__file__))
 
diff --git a/yt/utilities/tests/test_decompose.py b/yt/utilities/tests/test_decompose.py
index 2ad83192442..1c45fe2b2ba 100644
--- a/yt/utilities/tests/test_decompose.py
+++ b/yt/utilities/tests/test_decompose.py
@@ -1,6 +1,7 @@
-from yt.testing import assert_array_equal, assert_almost_equal
 import numpy as np
+
 import yt.utilities.decompose as dec
+from yt.testing import assert_almost_equal, assert_array_equal
 
 
 def setup():
diff --git a/yt/utilities/tests/test_hierarchy_inspection.py b/yt/utilities/tests/test_hierarchy_inspection.py
index c343abb229d..a1883a0a93d 100644
--- a/yt/utilities/tests/test_hierarchy_inspection.py
+++ b/yt/utilities/tests/test_hierarchy_inspection.py
@@ -5,7 +5,8 @@
 @author: stuart
 """
 
-from .. hierarchy_inspection import find_lowest_subclasses
+from ..hierarchy_inspection import find_lowest_subclasses
+
 
 class level1:
     pass
diff --git a/yt/utilities/tests/test_interpolators.py b/yt/utilities/tests/test_interpolators.py
index 4f10dc0d98c..4ab219c5194 100644
--- a/yt/utilities/tests/test_interpolators.py
+++ b/yt/utilities/tests/test_interpolators.py
@@ -1,13 +1,11 @@
 import warnings
+
 import numpy as np
 
-from yt.testing import \
-    assert_array_equal, \
-    assert_array_almost_equal, \
-    fake_random_ds
 import yt.utilities.linear_interpolators as lin
-from yt.utilities.lib.interpolators import \
-    ghost_zone_interpolate
+from yt.testing import assert_array_almost_equal, assert_array_equal, fake_random_ds
+from yt.utilities.lib.interpolators import ghost_zone_interpolate
+
 
 def setup():
     pass
diff --git a/yt/utilities/tests/test_load_sample.py b/yt/utilities/tests/test_load_sample.py
index 66de0ad946f..192e3d649fa 100644
--- a/yt/utilities/tests/test_load_sample.py
+++ b/yt/utilities/tests/test_load_sample.py
@@ -30,4 +30,3 @@ def test_name_validator():
         assert_equal(fileext, expected_answers["fileext"])
         assert_equal(bname, expected_answers["basename"])
         assert_equal(ext, expected_answers["extension"])
-
diff --git a/yt/utilities/tests/test_minimal_representation.py b/yt/utilities/tests/test_minimal_representation.py
index 49bef305f01..e42d32388ed 100644
--- a/yt/utilities/tests/test_minimal_representation.py
+++ b/yt/utilities/tests/test_minimal_representation.py
@@ -1,8 +1,8 @@
 import os.path
+
 import yt
 from yt.config import ytcfg
-from yt.testing import \
-    assert_equal, requires_file, assert_raises
+from yt.testing import assert_equal, assert_raises, requires_file
 
 G30 = "IsolatedGalaxy/galaxy0030/galaxy0030"
 
diff --git a/yt/utilities/tests/test_particle_generator.py b/yt/utilities/tests/test_particle_generator.py
index 40aa56efc6b..314c1ee4fbe 100644
--- a/yt/utilities/tests/test_particle_generator.py
+++ b/yt/utilities/tests/test_particle_generator.py
@@ -1,15 +1,16 @@
 import numpy as np
-from yt.testing import \
-    assert_almost_equal, \
-    assert_equal
-from yt.utilities.particle_generator import \
-    WithDensityParticleGenerator, \
-    LatticeParticleGenerator, \
-    FromListParticleGenerator
-from yt.frontends.stream.api import load_uniform_grid, refine_amr
-import yt.utilities.initial_conditions as ic
+
 import yt.utilities.flagging_methods as fm
+import yt.utilities.initial_conditions as ic
+from yt.frontends.stream.api import load_uniform_grid, refine_amr
+from yt.testing import assert_almost_equal, assert_equal
 from yt.units.yt_array import uconcatenate
+from yt.utilities.particle_generator import (
+    FromListParticleGenerator,
+    LatticeParticleGenerator,
+    WithDensityParticleGenerator,
+)
+
 
 def test_particle_generator():
     # First generate our dataset
@@ -137,4 +138,3 @@ def new_indices():
     del fields
     del dens
     del temp
-
diff --git a/yt/utilities/tests/test_periodic_table.py b/yt/utilities/tests/test_periodic_table.py
index 96613dac164..fe7e8770229 100644
--- a/yt/utilities/tests/test_periodic_table.py
+++ b/yt/utilities/tests/test_periodic_table.py
@@ -1,6 +1,7 @@
 from yt.testing import assert_equal
 from yt.utilities.periodic_table import _elements, periodic_table
 
+
 def test_element_accuracy():
     for num, w, name, sym in _elements:
         e0 = periodic_table[num]
diff --git a/yt/utilities/tests/test_periodicity.py b/yt/utilities/tests/test_periodicity.py
index bfb6b1c4b63..ddf3dc987ba 100644
--- a/yt/utilities/tests/test_periodicity.py
+++ b/yt/utilities/tests/test_periodicity.py
@@ -1,10 +1,9 @@
 import numpy as np
 
-from yt.testing import \
-    fake_random_ds, \
-    assert_almost_equal
+from yt.testing import assert_almost_equal, fake_random_ds
 from yt.utilities.math_utils import euclidean_dist, periodic_dist
 
+
 def setup():
     from yt.config import ytcfg
     ytcfg["yt","__withintesting"] = "True"
diff --git a/yt/utilities/tests/test_selectors.py b/yt/utilities/tests/test_selectors.py
index 61c058de71f..4f570358bf2 100644
--- a/yt/utilities/tests/test_selectors.py
+++ b/yt/utilities/tests/test_selectors.py
@@ -1,6 +1,6 @@
 import numpy as np
-from yt.testing import \
-    fake_random_ds, assert_equal, assert_array_less
+
+from yt.testing import assert_array_less, assert_equal, fake_random_ds
 from yt.utilities.math_utils import periodic_dist
 
 
diff --git a/yt/visualization/__init__.py b/yt/visualization/__init__.py
index 938c0f5ff08..4a35d386919 100644
--- a/yt/visualization/__init__.py
+++ b/yt/visualization/__init__.py
@@ -9,4 +9,3 @@
 
 
 """
-
diff --git a/yt/visualization/_colormap_data.py b/yt/visualization/_colormap_data.py
index 3a4e68601b8..d5fc2c87cd2 100644
--- a/yt/visualization/_colormap_data.py
+++ b/yt/visualization/_colormap_data.py
@@ -2,6 +2,7 @@
 
 import numpy as np
 from numpy import array
+
 color_map_luts = {}
 
 
diff --git a/yt/visualization/_mpl_imports.py b/yt/visualization/_mpl_imports.py
index 71b87a2053b..ea8eeb873fa 100644
--- a/yt/visualization/_mpl_imports.py
+++ b/yt/visualization/_mpl_imports.py
@@ -1,14 +1,7 @@
 import matplotlib
-matplotlib.rc('contour', negative_linestyle='solid')
-
-from matplotlib.backends.backend_agg import \
-    FigureCanvasAgg
-
-from matplotlib.backends.backend_pdf import \
-    FigureCanvasPdf
+from matplotlib.backends.backend_agg import FigureCanvasAgg
+from matplotlib.backends.backend_pdf import FigureCanvasPdf
+from matplotlib.backends.backend_ps import FigureCanvasPS
+from matplotlib.backends.backend_svg import FigureCanvasSVG
 
-from matplotlib.backends.backend_ps import \
-    FigureCanvasPS
-
-from matplotlib.backends.backend_svg import \
-    FigureCanvasSVG
+matplotlib.rc('contour', negative_linestyle='solid')
diff --git a/yt/visualization/api.py b/yt/visualization/api.py
index 442d71181aa..c4fc33d84e0 100644
--- a/yt/visualization/api.py
+++ b/yt/visualization/api.py
@@ -1,57 +1,37 @@
-from .color_maps import \
-    add_colormap, \
-    show_colormaps, \
-    make_colormap
-
-from .particle_plots import \
-    ParticleProjectionPlot, \
-    ParticlePhasePlot, \
-    ParticlePlot
-
-from .fixed_resolution import \
-    FixedResolutionBuffer, \
-    ObliqueFixedResolutionBuffer, \
-    ParticleImageBuffer
-
-from .image_writer import \
-    multi_image_composite, \
-    write_bitmap, \
-    write_image, \
-    map_to_colors, \
-    splat_points, \
-    apply_colormap, \
-    scale_image, \
-    write_projection
-
-from .plot_modifications import \
-    PlotCallback, \
-    callback_registry
-
-from .streamlines import \
-    Streamlines
-
-from .plot_window import \
-    SlicePlot, \
-    AxisAlignedSlicePlot, \
-    OffAxisSlicePlot, \
-    ProjectionPlot, \
-    OffAxisProjectionPlot, \
-    plot_2d
-
-from .line_plot import \
-    LinePlot, \
-    LineBuffer
-
-from .profile_plotter import \
-    ProfilePlot, \
-    PhasePlot
-
-from .base_plot_types import \
-    get_multi_plot
-
-from .fits_image import \
-    FITSImageData, \
-    FITSSlice, \
-    FITSOffAxisSlice, \
-    FITSProjection, \
-    FITSOffAxisProjection
+from .base_plot_types import get_multi_plot
+from .color_maps import add_colormap, make_colormap, show_colormaps
+from .fits_image import (
+    FITSImageData,
+    FITSOffAxisProjection,
+    FITSOffAxisSlice,
+    FITSProjection,
+    FITSSlice,
+)
+from .fixed_resolution import (
+    FixedResolutionBuffer,
+    ObliqueFixedResolutionBuffer,
+    ParticleImageBuffer,
+)
+from .image_writer import (
+    apply_colormap,
+    map_to_colors,
+    multi_image_composite,
+    scale_image,
+    splat_points,
+    write_bitmap,
+    write_image,
+    write_projection,
+)
+from .line_plot import LineBuffer, LinePlot
+from .particle_plots import ParticlePhasePlot, ParticlePlot, ParticleProjectionPlot
+from .plot_modifications import PlotCallback, callback_registry
+from .plot_window import (
+    AxisAlignedSlicePlot,
+    OffAxisProjectionPlot,
+    OffAxisSlicePlot,
+    ProjectionPlot,
+    SlicePlot,
+    plot_2d,
+)
+from .profile_plotter import PhasePlot, ProfilePlot
+from .streamlines import Streamlines
diff --git a/yt/visualization/base_plot_types.py b/yt/visualization/base_plot_types.py
index 07bc37fde35..2270069ee96 100644
--- a/yt/visualization/base_plot_types.py
+++ b/yt/visualization/base_plot_types.py
@@ -1,17 +1,17 @@
-import matplotlib
-import numpy as np
-
 from distutils.version import LooseVersion
 from io import BytesIO
 
-from yt.funcs import \
-    get_image_suffix, \
-    mylog, \
-    iterable, \
-    get_brewer_cmap, \
-    matplotlib_style_context, \
-    get_interactivity
+import matplotlib
+import numpy as np
 
+from yt.funcs import (
+    get_brewer_cmap,
+    get_image_suffix,
+    get_interactivity,
+    iterable,
+    matplotlib_style_context,
+    mylog,
+)
 
 backend_dict = {'GTK': ['backend_gtk', 'FigureCanvasGTK',
                        'FigureManagerGTK'],
diff --git a/yt/visualization/color_maps.py b/yt/visualization/color_maps.py
index e3a70aac24d..00e27cad9d1 100644
--- a/yt/visualization/color_maps.py
+++ b/yt/visualization/color_maps.py
@@ -1,7 +1,7 @@
+import matplotlib.cm as mcm
+import matplotlib.colors as cc
 import numpy as np
 
-import matplotlib.colors as cc
-import matplotlib.cm as mcm
 from . import _colormap_data as _cm
 
 try:
diff --git a/yt/visualization/eps_writer.py b/yt/visualization/eps_writer.py
index 11bcdaccd42..bc7af378f8f 100644
--- a/yt/visualization/eps_writer.py
+++ b/yt/visualization/eps_writer.py
@@ -1,16 +1,17 @@
-import pyx
+import matplotlib.pyplot as plt
 import numpy as np
 from matplotlib import cm
-import matplotlib.pyplot as plt
 
-from yt.config import \
-    ytcfg
+import pyx
+from yt.config import ytcfg
+from yt.funcs import issue_deprecation_warning
+from yt.units.unit_object import Unit
+from yt.units.yt_array import YTQuantity
 from yt.utilities.logger import ytLogger as mylog
+
 from .plot_window import PlotWindow
 from .profile_plotter import PhasePlot, ProfilePlot
-from yt.units.yt_array import YTQuantity
-from yt.units.unit_object import Unit
-from yt.funcs import issue_deprecation_warning
+
 
 def convert_frac_to_tex(string):
     frac_pos = string.find(r'\frac')
@@ -1366,4 +1367,3 @@ def return_colormap(cmap=None, label="", range=(0,1), log=False):
     if cmap is None:
         cmap = ytcfg.get("yt", "default_colormap")
     return {'cmap': cmap, 'name': label, 'range': range, 'log': log}
-    
diff --git a/yt/visualization/fits_image.py b/yt/visualization/fits_image.py
index e73567d70c9..14fc9c2204b 100644
--- a/yt/visualization/fits_image.py
+++ b/yt/visualization/fits_image.py
@@ -1,23 +1,22 @@
-import numpy as np
-from itertools import count
-from yt.fields.derived_field import DerivedField
-from yt.funcs import mylog, iterable, fix_axis, ensure_list, \
-    issue_deprecation_warning
-from yt.visualization.fixed_resolution import FixedResolutionBuffer
-from yt.data_objects.image_array import ImageArray
-from yt.data_objects.construction_data_containers import YTCoveringGrid
-from yt.utilities.on_demand_imports import _astropy
-from yt.units.yt_array import YTQuantity, YTArray
-from yt.units.unit_object import Unit
-from yt.units import dimensions
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    parallel_root_only
-from yt.visualization.volume_rendering.off_axis_projection import \
-    off_axis_projection
 import re
 import sys
+from itertools import count
 from numbers import Number as numeric_type
 
+import numpy as np
+
+from yt.data_objects.construction_data_containers import YTCoveringGrid
+from yt.data_objects.image_array import ImageArray
+from yt.fields.derived_field import DerivedField
+from yt.funcs import ensure_list, fix_axis, issue_deprecation_warning, iterable, mylog
+from yt.units import dimensions
+from yt.units.unit_object import Unit
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.on_demand_imports import _astropy
+from yt.utilities.parallel_tools.parallel_analysis_interface import parallel_root_only
+from yt.visualization.fixed_resolution import FixedResolutionBuffer
+from yt.visualization.volume_rendering.off_axis_projection import off_axis_projection
+
 
 class UnitfulHDU:
     def __init__(self, hdu):
diff --git a/yt/visualization/fixed_resolution.py b/yt/visualization/fixed_resolution.py
index b16bd8f8b19..3388b01f053 100644
--- a/yt/visualization/fixed_resolution.py
+++ b/yt/visualization/fixed_resolution.py
@@ -1,23 +1,25 @@
-from yt.frontends.ytdata.utilities import \
-    save_as_dataset
-from yt.funcs import \
-    get_output_filename, \
-    mylog, \
-    ensure_list, \
-    deprecate, \
-    issue_deprecation_warning
-from .volume_rendering.api import off_axis_projection
-from .fixed_resolution_filters import apply_filter, filter_registry
+import types
+import weakref
+
+import numpy as np
+
 from yt.data_objects.image_array import ImageArray
-from yt.utilities.lib.pixelization_routines import \
-    pixelize_cylinder
+from yt.frontends.stream.api import load_uniform_grid
+from yt.frontends.ytdata.utilities import save_as_dataset
+from yt.funcs import (
+    deprecate,
+    ensure_list,
+    get_output_filename,
+    issue_deprecation_warning,
+    mylog,
+)
 from yt.utilities.lib.api import add_points_to_greyscale_image
+from yt.utilities.lib.pixelization_routines import pixelize_cylinder
 from yt.utilities.on_demand_imports import _h5py as h5py
-from yt.frontends.stream.api import load_uniform_grid
 
-import numpy as np
-import weakref
-import types
+from .fixed_resolution_filters import apply_filter, filter_registry
+from .volume_rendering.api import off_axis_projection
+
 
 class FixedResolutionBuffer:
     r"""
diff --git a/yt/visualization/fixed_resolution_filters.py b/yt/visualization/fixed_resolution_filters.py
index 801b6f776de..3cf98728672 100644
--- a/yt/visualization/fixed_resolution_filters.py
+++ b/yt/visualization/fixed_resolution_filters.py
@@ -1,6 +1,7 @@
-import numpy as np
 from functools import wraps
 
+import numpy as np
+
 filter_registry = {}
 
 
diff --git a/yt/visualization/image_writer.py b/yt/visualization/image_writer.py
index c36f3303a3a..1fccf921dc4 100644
--- a/yt/visualization/image_writer.py
+++ b/yt/visualization/image_writer.py
@@ -1,18 +1,16 @@
+import builtins
+
 import numpy as np
 
-from yt.config import \
-    ytcfg
-from yt.funcs import \
-    mylog, \
-    get_image_suffix, \
-    get_brewer_cmap
+import yt.utilities.lib.image_utilities as au
+import yt.utilities.png_writer as pw
+from yt.config import ytcfg
+from yt.funcs import get_brewer_cmap, get_image_suffix, mylog
 from yt.units.yt_array import YTQuantity
 from yt.utilities.exceptions import YTNotInsideNotebook
-from .color_maps import mcm
+
 from . import _colormap_data as cmd
-import yt.utilities.lib.image_utilities as au
-import yt.utilities.png_writer as pw
-import builtins
+from .color_maps import mcm
 
 
 def scale_image(image, mi=None, ma=None):
@@ -441,4 +439,3 @@ def display_in_notebook(image, max_val=None):
         )
     else:
         raise YTNotInsideNotebook
-
diff --git a/yt/visualization/line_plot.py b/yt/visualization/line_plot.py
index dbe91b07c9b..1814107f0f3 100644
--- a/yt/visualization/line_plot.py
+++ b/yt/visualization/line_plot.py
@@ -1,21 +1,19 @@
+from collections import defaultdict
+
 import numpy as np
 
-from collections import defaultdict
-from yt.funcs import \
-    iterable, \
-    mylog
-from yt.units.unit_object import \
-    Unit
-from yt.units.yt_array import \
-    YTArray
-from yt.visualization.base_plot_types import \
-    PlotMPL
-from yt.visualization.plot_container import \
-    PlotContainer, \
-    PlotDictionary, \
-    log_transform, \
-    linear_transform, \
-    invalidate_plot
+from yt.funcs import iterable, mylog
+from yt.units.unit_object import Unit
+from yt.units.yt_array import YTArray
+from yt.visualization.base_plot_types import PlotMPL
+from yt.visualization.plot_container import (
+    PlotContainer,
+    PlotDictionary,
+    invalidate_plot,
+    linear_transform,
+    log_transform,
+)
+
 
 class LineBuffer:
     r"""
diff --git a/yt/visualization/mapserver/pannable_map.py b/yt/visualization/mapserver/pannable_map.py
index 73fe2b24382..77b82d06c0f 100644
--- a/yt/visualization/mapserver/pannable_map.py
+++ b/yt/visualization/mapserver/pannable_map.py
@@ -1,14 +1,13 @@
 import os
-import numpy as np
-
 from functools import wraps
 
-from yt.visualization.image_writer import apply_colormap
-from yt.visualization.fixed_resolution import FixedResolutionBuffer
-from yt.utilities.lib.misc_utilities import get_color_bounds
-from yt.utilities.png_writer import write_png_to_string
+import numpy as np
 
 import bottle
+from yt.utilities.lib.misc_utilities import get_color_bounds
+from yt.utilities.png_writer import write_png_to_string
+from yt.visualization.fixed_resolution import FixedResolutionBuffer
+from yt.visualization.image_writer import apply_colormap
 
 local_dir = os.path.dirname(__file__)
 
diff --git a/yt/visualization/particle_plots.py b/yt/visualization/particle_plots.py
index 3aa7a6e1351..c0b07d5bdbd 100644
--- a/yt/visualization/particle_plots.py
+++ b/yt/visualization/particle_plots.py
@@ -1,19 +1,12 @@
 import numpy as np
 
-from yt.visualization.fixed_resolution import \
-    ParticleImageBuffer
-from yt.funcs import \
-    ensure_list, \
-    fix_axis
+from yt.data_objects.profiles import create_profile
+from yt.funcs import ensure_list, fix_axis
 from yt.units.yt_array import YTArray
-from .plot_window import \
-    get_axes_unit, \
-    get_window_parameters, \
-    PWViewerMPL
-from yt.data_objects.profiles import \
-    create_profile
-from yt.visualization.profile_plotter import \
-    PhasePlot
+from yt.visualization.fixed_resolution import ParticleImageBuffer
+from yt.visualization.profile_plotter import PhasePlot
+
+from .plot_window import PWViewerMPL, get_axes_unit, get_window_parameters
 
 
 class ParticleAxisAlignedDummyDataSource:
diff --git a/yt/visualization/plot_container.py b/yt/visualization/plot_container.py
index 853a952cb3d..732021e9966 100644
--- a/yt/visualization/plot_container.py
+++ b/yt/visualization/plot_container.py
@@ -1,33 +1,27 @@
-import builtins
-from yt.funcs import mylog
-from yt.units import YTQuantity
-
 import base64
-import numpy as np
-import matplotlib
+import builtins
 import os
-
 from collections import defaultdict
 from functools import wraps
 
-from yt.config import \
-    ytcfg
-from yt.data_objects.time_series import \
-    DatasetSeries
-from yt.funcs import \
-    get_image_suffix, \
-    iterable, \
-    ensure_dir, \
-    ensure_list, \
-    issue_deprecation_warning
-from yt.units.unit_object import \
-    Unit
-from yt.utilities.definitions import \
-    formatted_length_unit_names
-from yt.utilities.exceptions import \
-    YTNotInsideNotebook
-from yt.visualization.color_maps import \
-    yt_colormaps
+import matplotlib
+import numpy as np
+
+from yt.config import ytcfg
+from yt.data_objects.time_series import DatasetSeries
+from yt.funcs import (
+    ensure_dir,
+    ensure_list,
+    get_image_suffix,
+    issue_deprecation_warning,
+    iterable,
+    mylog,
+)
+from yt.units import YTQuantity
+from yt.units.unit_object import Unit
+from yt.utilities.definitions import formatted_length_unit_names
+from yt.utilities.exceptions import YTNotInsideNotebook
+from yt.visualization.color_maps import yt_colormaps
 
 latex_prefixes = {
     "u": r"\mu",
diff --git a/yt/visualization/plot_modifications.py b/yt/visualization/plot_modifications.py
index 84e16430bcf..a9b4c93ccd9 100644
--- a/yt/visualization/plot_modifications.py
+++ b/yt/visualization/plot_modifications.py
@@ -1,48 +1,35 @@
 
 
+import re
 import warnings
+from functools import wraps
+from numbers import Number
 
 import matplotlib
 import numpy as np
-import re
-
-from functools import wraps
 
-from numbers import Number
-
-from yt.data_objects.level_sets.clump_handling import \
-    Clump
-from yt.frontends.ytdata.data_structures import \
-    YTClumpContainer
+from yt.data_objects.data_containers import YTDataContainer
+from yt.data_objects.level_sets.clump_handling import Clump
 from yt.data_objects.selection_data_containers import YTCutRegion
-from yt.data_objects.data_containers import \
-    YTDataContainer
-from yt.data_objects.static_output import \
-    Dataset
-from yt.funcs import \
-    iterable, \
-    mylog, \
-    validate_width_tuple
-from yt.geometry.geometry_handler import \
-    is_curvilinear
+from yt.data_objects.static_output import Dataset
+from yt.frontends.ytdata.data_structures import YTClumpContainer
+from yt.funcs import iterable, mylog, validate_width_tuple
+from yt.geometry.geometry_handler import is_curvilinear
+from yt.geometry.unstructured_mesh_handler import UnstructuredIndex
 from yt.units import dimensions
-from yt.units.yt_array import YTQuantity, YTArray, uhstack
 from yt.units.unit_object import Unit
-from yt.visualization.image_writer import apply_colormap
+from yt.units.yt_array import YTArray, YTQuantity, uhstack
+from yt.utilities.exceptions import YTDataTypeUnsupported
 from yt.utilities.lib.geometry_utils import triangle_plane_intersect
-from yt.utilities.lib.pixelization_routines import \
-    pixelize_off_axis_cartesian, \
-    pixelize_cartesian
-from yt.utilities.lib.line_integral_convolution import \
-    line_integral_convolution_2d
-from yt.geometry.unstructured_mesh_handler import UnstructuredIndex
+from yt.utilities.lib.line_integral_convolution import line_integral_convolution_2d
 from yt.utilities.lib.mesh_triangulation import triangulate_indices
-from yt.utilities.exceptions import \
-    YTDataTypeUnsupported
-from yt.utilities.math_utils import \
-    periodic_ray
-from yt.utilities.on_demand_imports import \
-    NotAModule
+from yt.utilities.lib.pixelization_routines import (
+    pixelize_cartesian,
+    pixelize_off_axis_cartesian,
+)
+from yt.utilities.math_utils import periodic_ray
+from yt.utilities.on_demand_imports import NotAModule
+from yt.visualization.image_writer import apply_colormap
 
 callback_registry = {}
 
diff --git a/yt/visualization/plot_window.py b/yt/visualization/plot_window.py
index 59f2a6feb74..073deeae957 100644
--- a/yt/visualization/plot_window.py
+++ b/yt/visualization/plot_window.py
@@ -1,53 +1,56 @@
-import numpy as np
-import matplotlib
-import types
 import sys
-
+import types
 from collections import defaultdict
 from distutils.version import LooseVersion
 from numbers import Number
 
-from .base_plot_types import \
-    ImagePlotMPL
-from .fixed_resolution import \
-    FixedResolutionBuffer, \
-    OffAxisProjectionFixedResolutionBuffer
-from .plot_modifications import callback_registry
-from .plot_container import \
-    ImagePlotContainer, \
-    log_transform, linear_transform, symlog_transform, \
-    get_log_minorticks, get_symlog_minorticks, \
-    invalidate_data, invalidate_plot, invalidate_figure, \
-    apply_callback
-from .base_plot_types import CallbackWrapper
-
-from yt.data_objects.image_array import \
-    ImageArray
-from yt.frontends.ytdata.data_structures import \
-    YTSpatialPlotDataset
-from yt.funcs import \
-    mylog, iterable, ensure_list, \
-    fix_axis, fix_unitary, obj_length, \
-    issue_deprecation_warning
-from yt.units.unit_object import \
-    Unit
-from yt.units.unit_registry import \
-    UnitParseError
-from yt.units.yt_array import \
-    YTArray, YTQuantity
-from yt.utilities.math_utils import \
-    ortho_find
-from yt.utilities.orientation import \
-    Orientation
-from yt.utilities.exceptions import \
-    YTCannotParseUnitDisplayName, \
-    YTPlotCallbackError, \
-    YTDataTypeUnsupported, \
-    YTInvalidFieldType, \
-    YTUnitNotRecognized
+import matplotlib
+import numpy as np
 from unyt.exceptions import UnitConversionError
 
+from yt.data_objects.image_array import ImageArray
+from yt.frontends.ytdata.data_structures import YTSpatialPlotDataset
+from yt.funcs import (
+    ensure_list,
+    fix_axis,
+    fix_unitary,
+    issue_deprecation_warning,
+    iterable,
+    mylog,
+    obj_length,
+)
+from yt.units.unit_object import Unit
+from yt.units.unit_registry import UnitParseError
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.exceptions import (
+    YTCannotParseUnitDisplayName,
+    YTDataTypeUnsupported,
+    YTInvalidFieldType,
+    YTPlotCallbackError,
+    YTUnitNotRecognized,
+)
+from yt.utilities.math_utils import ortho_find
+from yt.utilities.orientation import Orientation
+
+from .base_plot_types import CallbackWrapper, ImagePlotMPL
+from .fixed_resolution import (
+    FixedResolutionBuffer,
+    OffAxisProjectionFixedResolutionBuffer,
+)
 from .geo_plot_utils import get_mpl_transform
+from .plot_container import (
+    ImagePlotContainer,
+    apply_callback,
+    get_log_minorticks,
+    get_symlog_minorticks,
+    invalidate_data,
+    invalidate_figure,
+    invalidate_plot,
+    linear_transform,
+    log_transform,
+    symlog_transform,
+)
+from .plot_modifications import callback_registry
 
 MPL_VERSION = LooseVersion(matplotlib.__version__)
 
diff --git a/yt/visualization/profile_plotter.py b/yt/visualization/profile_plotter.py
index a18140c9be7..33f1ed3984f 100644
--- a/yt/visualization/profile_plotter.py
+++ b/yt/visualization/profile_plotter.py
@@ -1,35 +1,30 @@
+import base64
 import builtins
+import os
 from collections import OrderedDict
 from distutils.version import LooseVersion
-import base64
-import os
 from functools import wraps
 
 import matplotlib
 import numpy as np
 
-from .base_plot_types import \
-    PlotMPL, ImagePlotMPL
-from .plot_container import \
-    ImagePlotContainer, \
-    log_transform, linear_transform, get_log_minorticks, \
-    validate_plot, invalidate_plot
-from yt.data_objects.profiles import \
-    create_profile, sanitize_field_tuple_keys
-from yt.data_objects.static_output import \
-    Dataset
-from yt.data_objects.data_containers import \
-    YTSelectionContainer
-from yt.frontends.ytdata.data_structures import \
-    YTProfileDataset
-from yt.utilities.exceptions import \
-    YTNotInsideNotebook
+from yt.data_objects.data_containers import YTSelectionContainer
+from yt.data_objects.profiles import create_profile, sanitize_field_tuple_keys
+from yt.data_objects.static_output import Dataset
+from yt.frontends.ytdata.data_structures import YTProfileDataset
+from yt.funcs import ensure_list, get_image_suffix, iterable, matplotlib_style_context
+from yt.utilities.exceptions import YTNotInsideNotebook
 from yt.utilities.logger import ytLogger as mylog
-from yt.funcs import \
-    ensure_list, \
-    get_image_suffix, \
-    matplotlib_style_context, \
-    iterable
+
+from .base_plot_types import ImagePlotMPL, PlotMPL
+from .plot_container import (
+    ImagePlotContainer,
+    get_log_minorticks,
+    invalidate_plot,
+    linear_transform,
+    log_transform,
+    validate_plot,
+)
 
 MPL_VERSION = LooseVersion(matplotlib.__version__)
 
diff --git a/yt/visualization/streamlines.py b/yt/visualization/streamlines.py
index acd6872a36c..97246e078ff 100644
--- a/yt/visualization/streamlines.py
+++ b/yt/visualization/streamlines.py
@@ -1,10 +1,14 @@
 import numpy as np
+
 from yt.data_objects.construction_data_containers import YTStreamline
 from yt.funcs import get_pbar
 from yt.units.yt_array import YTArray
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    ParallelAnalysisInterface, parallel_passthrough
 from yt.utilities.amr_kdtree.api import AMRKDTree
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    ParallelAnalysisInterface,
+    parallel_passthrough,
+)
+
 
 def sanitize_length(length, ds):
     # Ensure that lengths passed in with units are returned as code_length
diff --git a/yt/visualization/tests/test_callbacks.py b/yt/visualization/tests/test_callbacks.py
index 26d8441e8a7..4c8daf1ca46 100644
--- a/yt/visualization/tests/test_callbacks.py
+++ b/yt/visualization/tests/test_callbacks.py
@@ -1,29 +1,24 @@
-import tempfile
+import contextlib
 import shutil
-from numpy.testing import \
-    assert_raises, \
-    assert_array_equal
-
-from yt.config import \
-    ytcfg
-from yt.testing import \
-    fake_amr_ds, \
-    fake_random_ds, \
-    fake_tetrahedral_ds, \
-    fake_hexahedral_ds, \
-    assert_fname, \
-    requires_file
+import tempfile
+
+from numpy.testing import assert_array_equal, assert_raises
+
 import yt.units as u
-from yt.utilities.exceptions import \
-    YTPlotCallbackError, \
-    YTDataTypeUnsupported
-from yt.visualization.api import \
-    SlicePlot, ProjectionPlot, OffAxisSlicePlot
+from yt.config import ytcfg
 from yt.convenience import load
+from yt.testing import (
+    assert_fname,
+    fake_amr_ds,
+    fake_hexahedral_ds,
+    fake_random_ds,
+    fake_tetrahedral_ds,
+    requires_file,
+)
+from yt.utilities.exceptions import YTDataTypeUnsupported, YTPlotCallbackError
+from yt.visualization.api import OffAxisSlicePlot, ProjectionPlot, SlicePlot
 from yt.visualization.plot_container import accepts_all_fields
 
-import contextlib
-
 # These are a very simple set of tests that verify that each callback is or is
 # not working.  They only check that it functions without an error; they do not
 # check that it is providing correct results.
diff --git a/yt/visualization/tests/test_color_maps.py b/yt/visualization/tests/test_color_maps.py
index c83bd0987ff..6b072f8a802 100644
--- a/yt/visualization/tests/test_color_maps.py
+++ b/yt/visualization/tests/test_color_maps.py
@@ -6,8 +6,8 @@
 import numpy as np
 from nose.tools import assert_raises
 
-from yt import show_colormaps, make_colormap
-from yt.testing import assert_equal, assert_almost_equal, requires_backend
+from yt import make_colormap, show_colormaps
+from yt.testing import assert_almost_equal, assert_equal, requires_backend
 
 
 class TestColorMaps(unittest.TestCase):
diff --git a/yt/visualization/tests/test_export_frb.py b/yt/visualization/tests/test_export_frb.py
index 61c2ab68768..03a054bf6ae 100644
--- a/yt/visualization/tests/test_export_frb.py
+++ b/yt/visualization/tests/test_export_frb.py
@@ -1,7 +1,7 @@
 import numpy as np
-from yt.testing import \
-    fake_random_ds, assert_equal, \
-    assert_allclose_units
+
+from yt.testing import assert_allclose_units, assert_equal, fake_random_ds
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/tests/test_fits_image.py b/yt/visualization/tests/test_fits_image.py
index 487306d0363..1e43696240b 100644
--- a/yt/visualization/tests/test_fits_image.py
+++ b/yt/visualization/tests/test_fits_image.py
@@ -1,19 +1,21 @@
-import tempfile
 import os
 import shutil
-from yt.testing import fake_random_ds, requires_module
+import tempfile
+
+from numpy.testing import assert_allclose, assert_equal
+
 from yt.convenience import load
-from numpy.testing import \
-    assert_equal, \
-    assert_allclose
+from yt.testing import fake_random_ds, requires_module
 from yt.utilities.on_demand_imports import _astropy
-from yt.visualization.fits_image import \
-    FITSImageData, FITSProjection, \
-    FITSSlice, FITSOffAxisSlice, \
-    FITSOffAxisProjection, \
-    assert_same_wcs
-from yt.visualization.volume_rendering.off_axis_projection import \
-    off_axis_projection
+from yt.visualization.fits_image import (
+    FITSImageData,
+    FITSOffAxisProjection,
+    FITSOffAxisSlice,
+    FITSProjection,
+    FITSSlice,
+    assert_same_wcs,
+)
+from yt.visualization.volume_rendering.off_axis_projection import off_axis_projection
 
 
 @requires_module("astropy")
diff --git a/yt/visualization/tests/test_geo_projections.py b/yt/visualization/tests/test_geo_projections.py
index f1808ebf59b..d55b4588a4f 100644
--- a/yt/visualization/tests/test_geo_projections.py
+++ b/yt/visualization/tests/test_geo_projections.py
@@ -1,13 +1,12 @@
+import unittest
+
 from nose.plugins.attrib import attr
 
 import yt
-import unittest
-from yt.testing import \
-    ANSWER_TEST_TAG, \
-    fake_amr_ds, \
-    requires_module
+from yt.testing import ANSWER_TEST_TAG, fake_amr_ds, requires_module
 from yt.utilities.answer_testing.framework import GenericImageTest
-from yt.visualization.geo_plot_utils import transform_list, get_mpl_transform
+from yt.visualization.geo_plot_utils import get_mpl_transform, transform_list
+
 
 def setup():
     """Test specific setup."""
@@ -146,4 +145,3 @@ def test_projection_setup(self):
         assert self.ds.coordinates.data_transform[axis] is None
         assert self.slc._projection is None
         assert self.slc._transform is None
-
diff --git a/yt/visualization/tests/test_image_writer.py b/yt/visualization/tests/test_image_writer.py
index 3fa6b6c2849..305fc983eb5 100644
--- a/yt/visualization/tests/test_image_writer.py
+++ b/yt/visualization/tests/test_image_writer.py
@@ -6,9 +6,14 @@
 import numpy as np
 from nose.tools import assert_raises
 
-from yt.testing import fake_random_ds, assert_equal
-from yt.visualization.image_writer import multi_image_composite, splat_points, \
-    write_bitmap, apply_colormap, strip_colormap_data
+from yt.testing import assert_equal, fake_random_ds
+from yt.visualization.image_writer import (
+    apply_colormap,
+    multi_image_composite,
+    splat_points,
+    strip_colormap_data,
+    write_bitmap,
+)
 
 
 class TestImageWriter(unittest.TestCase):
diff --git a/yt/visualization/tests/test_line_plots.py b/yt/visualization/tests/test_line_plots.py
index df719566f3c..be28bba039c 100644
--- a/yt/visualization/tests/test_line_plots.py
+++ b/yt/visualization/tests/test_line_plots.py
@@ -2,10 +2,11 @@
 from nose.tools import assert_raises
 
 import yt
-from yt.testing import assert_equal, fake_random_ds, ANSWER_TEST_TAG
+from yt.testing import ANSWER_TEST_TAG, assert_equal, fake_random_ds
 from yt.utilities.answer_testing.framework import GenericImageTest
 from yt.visualization.line_plot import _validate_point
 
+
 def setup():
     """Test specific setup."""
     from yt.config import ytcfg
diff --git a/yt/visualization/tests/test_mesh_slices.py b/yt/visualization/tests/test_mesh_slices.py
index 9c96b61c6be..c79b7a209d8 100644
--- a/yt/visualization/tests/test_mesh_slices.py
+++ b/yt/visualization/tests/test_mesh_slices.py
@@ -2,8 +2,13 @@
 from nose.plugins.attrib import attr
 
 import yt
-from yt.testing import ANSWER_TEST_TAG, fake_amr_ds, fake_tetrahedral_ds, \
-    fake_hexahedral_ds, small_fake_hexahedral_ds
+from yt.testing import (
+    ANSWER_TEST_TAG,
+    fake_amr_ds,
+    fake_hexahedral_ds,
+    fake_tetrahedral_ds,
+    small_fake_hexahedral_ds,
+)
 from yt.utilities.answer_testing.framework import GenericImageTest
 from yt.utilities.lib.geometry_utils import triangle_plane_intersect
 from yt.utilities.lib.mesh_triangulation import triangulate_indices
diff --git a/yt/visualization/tests/test_offaxisprojection.py b/yt/visualization/tests/test_offaxisprojection.py
index 59ee958b0e8..d1d6f12b9ad 100644
--- a/yt/visualization/tests/test_offaxisprojection.py
+++ b/yt/visualization/tests/test_offaxisprojection.py
@@ -3,16 +3,17 @@
 import tempfile
 import unittest
 
+from yt.testing import (
+    assert_equal,
+    assert_fname,
+    expand_keywords,
+    fake_octree_ds,
+    fake_random_ds,
+)
+from yt.visualization.api import OffAxisProjectionPlot, OffAxisSlicePlot
 from yt.visualization.image_writer import write_projection
-from yt.testing import \
-    assert_equal, \
-    assert_fname, \
-    expand_keywords, \
-    fake_octree_ds, \
-    fake_random_ds
 from yt.visualization.volume_rendering.api import off_axis_projection
-from yt.visualization.api import OffAxisProjectionPlot, \
-    OffAxisSlicePlot
+
 
 class TestOffAxisProjection(unittest.TestCase):
     @classmethod
diff --git a/yt/visualization/tests/test_particle_plot.py b/yt/visualization/tests/test_particle_plot.py
index 872b1bb9b90..1da5d9f4c36 100644
--- a/yt/visualization/tests/test_particle_plot.py
+++ b/yt/visualization/tests/test_particle_plot.py
@@ -1,31 +1,30 @@
 import os
-import tempfile
 import shutil
+import tempfile
 import unittest
 
 import numpy as np
 
-from yt.data_objects.profiles import create_profile
-from yt.visualization.tests.test_plotwindow import \
-    WIDTH_SPECS, ATTR_ARGS
 from yt.convenience import load
 from yt.data_objects.particle_filters import add_particle_filter
-from yt.testing import \
-    fake_particle_ds, \
-    assert_array_almost_equal, \
-    requires_file, \
-    assert_allclose, \
-    assert_fname
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load, \
-    PlotWindowAttributeTest, \
-    PhasePlotAttributeTest
-from yt.visualization.api import \
-    ParticlePlot, \
-    ParticleProjectionPlot, \
-    ParticlePhasePlot
+from yt.data_objects.profiles import create_profile
+from yt.testing import (
+    assert_allclose,
+    assert_array_almost_equal,
+    assert_fname,
+    fake_particle_ds,
+    requires_file,
+)
 from yt.units.yt_array import YTArray
+from yt.utilities.answer_testing.framework import (
+    PhasePlotAttributeTest,
+    PlotWindowAttributeTest,
+    data_dir_load,
+    requires_ds,
+)
+from yt.visualization.api import ParticlePhasePlot, ParticlePlot, ParticleProjectionPlot
+from yt.visualization.tests.test_plotwindow import ATTR_ARGS, WIDTH_SPECS
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/tests/test_plotwindow.py b/yt/visualization/tests/test_plotwindow.py
index c237c9c3b29..c54c1ffa0ac 100644
--- a/yt/visualization/tests/test_plotwindow.py
+++ b/yt/visualization/tests/test_plotwindow.py
@@ -1,30 +1,43 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
-import matplotlib
-import numpy as np
 import os
 import shutil
 import tempfile
 import unittest
-
+from collections import OrderedDict
 from distutils.version import LooseVersion
+
+import matplotlib
+import numpy as np
 from nose.tools import assert_true
 
-from yt.testing import \
-    requires_file, \
-    fake_random_ds, assert_equal, assert_rel_equal, assert_array_equal, \
-    assert_array_almost_equal, assert_raises, assert_fname
-from yt.utilities.answer_testing.framework import \
-    requires_ds, data_dir_load, PlotWindowAttributeTest
-from yt.utilities.exceptions import \
-    YTInvalidFieldType
-from yt.visualization.api import \
-    SlicePlot, ProjectionPlot, OffAxisSlicePlot, OffAxisProjectionPlot, \
-    plot_2d
-from yt.units.yt_array import YTArray, YTQuantity
-from yt.units import kboltz
 from yt.frontends.stream.api import load_uniform_grid
-from collections import OrderedDict
+from yt.testing import (
+    assert_array_almost_equal,
+    assert_array_equal,
+    assert_equal,
+    assert_fname,
+    assert_raises,
+    assert_rel_equal,
+    fake_random_ds,
+    requires_file,
+)
+from yt.units import kboltz
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.answer_testing.framework import (
+    PlotWindowAttributeTest,
+    data_dir_load,
+    requires_ds,
+)
+from yt.utilities.exceptions import YTInvalidFieldType
+from yt.visualization.api import (
+    OffAxisProjectionPlot,
+    OffAxisSlicePlot,
+    ProjectionPlot,
+    SlicePlot,
+    plot_2d,
+)
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/tests/test_profile_plots.py b/yt/visualization/tests/test_profile_plots.py
index 9f68ad932f4..d216e98dadf 100644
--- a/yt/visualization/tests/test_profile_plots.py
+++ b/yt/visualization/tests/test_profile_plots.py
@@ -1,18 +1,23 @@
 import os
-import tempfile
 import shutil
+import tempfile
 import unittest
-import yt
+
 from nose.plugins.attrib import attr
+
+import yt
 from yt.data_objects.profiles import create_profile
-from yt.testing import \
-    fake_random_ds, \
-    assert_array_almost_equal, \
-    assert_allclose_units, ANSWER_TEST_TAG
-from yt.visualization.profile_plotter import \
-    ProfilePlot, PhasePlot
-from yt.utilities.answer_testing.framework import \
-    PhasePlotAttributeTest, GenericImageTest
+from yt.testing import (
+    ANSWER_TEST_TAG,
+    assert_allclose_units,
+    assert_array_almost_equal,
+    fake_random_ds,
+)
+from yt.utilities.answer_testing.framework import (
+    GenericImageTest,
+    PhasePlotAttributeTest,
+)
+from yt.visualization.profile_plotter import PhasePlot, ProfilePlot
 
 ATTR_ARGS = {"annotate_text": [(((5e-29, 5e7), "Hello YT"), {}),
                                (((5e-29, 5e7), "Hello YT"), {'color': 'b'})],
@@ -277,7 +282,3 @@ def test_phaseplot_showhide_colorbar_axes():
     plot.show_axes()
     with tempfile.NamedTemporaryFile(suffix='png') as f4:
         plot.save(f4.name)
-
-
-
-
diff --git a/yt/visualization/tests/test_raw_field_slices.py b/yt/visualization/tests/test_raw_field_slices.py
index 891d416433d..1aeea2edf1a 100644
--- a/yt/visualization/tests/test_raw_field_slices.py
+++ b/yt/visualization/tests/test_raw_field_slices.py
@@ -1,8 +1,9 @@
 import yt
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load, \
-    GenericImageTest
+from yt.utilities.answer_testing.framework import (
+    GenericImageTest,
+    data_dir_load,
+    requires_ds,
+)
 
 
 def setup():
@@ -38,4 +39,3 @@ def test_raw_field_slices():
     ds = data_dir_load(raw_fields)
     for field in _raw_field_names:
         yield compare(ds, field, "answers_raw_%s" % field[1])
-
diff --git a/yt/visualization/tests/test_splat.py b/yt/visualization/tests/test_splat.py
index 131ba2e25cd..2b5531e80a4 100644
--- a/yt/visualization/tests/test_splat.py
+++ b/yt/visualization/tests/test_splat.py
@@ -1,11 +1,12 @@
 import os
 import os.path
-import tempfile
 import shutil
+import tempfile
+
 import numpy as np
+
 import yt
-from yt.testing import \
-    assert_equal
+from yt.testing import assert_equal
 from yt.utilities.lib.api import add_rgba_points_to_image
 
 
diff --git a/yt/visualization/volume_rendering/__init__.py b/yt/visualization/volume_rendering/__init__.py
index ee2b9899dde..d2b74ec8e56 100644
--- a/yt/visualization/volume_rendering/__init__.py
+++ b/yt/visualization/volume_rendering/__init__.py
@@ -4,4 +4,3 @@
 
 
 """
-
diff --git a/yt/visualization/volume_rendering/api.py b/yt/visualization/volume_rendering/api.py
index 21f9f4ee19a..fcc98be62c6 100644
--- a/yt/visualization/volume_rendering/api.py
+++ b/yt/visualization/volume_rendering/api.py
@@ -1,17 +1,25 @@
-from .transfer_functions import TransferFunction, ColorTransferFunction, \
-                             PlanckTransferFunction, \
-                             MultiVariateTransferFunction, \
-                             ProjectionTransferFunction
-from .image_handling import export_rgba, import_rgba, \
-                           plot_channel, plot_rgb
-
 from .camera import Camera
-from .transfer_function_helper import TransferFunctionHelper
-from .volume_rendering import volume_render, create_scene
+from .image_handling import export_rgba, import_rgba, plot_channel, plot_rgb
+from .interactive_vr_helpers import interactive_render
 from .off_axis_projection import off_axis_projection
+from .render_source import (
+    BoxSource,
+    CoordinateVectorSource,
+    GridSource,
+    LineSource,
+    MeshSource,
+    OpaqueSource,
+    PointSource,
+    VolumeSource,
+)
 from .scene import Scene
-from .render_source import VolumeSource, OpaqueSource, LineSource, \
-    BoxSource, PointSource, CoordinateVectorSource, GridSource, \
-    MeshSource
+from .transfer_function_helper import TransferFunctionHelper
+from .transfer_functions import (
+    ColorTransferFunction,
+    MultiVariateTransferFunction,
+    PlanckTransferFunction,
+    ProjectionTransferFunction,
+    TransferFunction,
+)
+from .volume_rendering import create_scene, volume_render
 from .zbuffer_array import ZBuffer
-from .interactive_vr_helpers import interactive_render
diff --git a/yt/visualization/volume_rendering/blenders.py b/yt/visualization/volume_rendering/blenders.py
index 23f512e72db..bd13fdede3a 100644
--- a/yt/visualization/volume_rendering/blenders.py
+++ b/yt/visualization/volume_rendering/blenders.py
@@ -1,5 +1,6 @@
 import numpy as np
 
+
 def enhance(im, stdval=6.0, just_alpha=True):
     if just_alpha:
         nz = im[im>0.0]
@@ -25,4 +26,3 @@ def enhance_rgba(im, stdval=6.0):
 
     im.rescale(amax=amax, cmax=cmax, inline=True)
     np.clip(im, 0.0, 1.0, im)
-
diff --git a/yt/visualization/volume_rendering/camera.py b/yt/visualization/volume_rendering/camera.py
index adfac3cbbe9..037831e1aa8 100644
--- a/yt/visualization/volume_rendering/camera.py
+++ b/yt/visualization/volume_rendering/camera.py
@@ -1,16 +1,16 @@
-from yt.funcs import iterable, ensure_numpy_array
-from yt.utilities.orientation import Orientation
-from yt.units.yt_array import \
-    YTArray, \
-    YTQuantity
+import weakref
+from numbers import Number as numeric_type
+
+import numpy as np
+
+from yt.funcs import ensure_numpy_array, iterable
+from yt.units.yt_array import YTArray, YTQuantity
 from yt.utilities.math_utils import get_rotation_matrix
+from yt.utilities.orientation import Orientation
+
+from .lens import Lens, lenses
 from .utils import data_source_or_all
-from .lens import \
-    lenses, \
-    Lens
-import numpy as np
-from numbers import Number as numeric_type
-import weakref
+
 
 def _sanitize_camera_property_units(value, scene):
     if iterable(value):
diff --git a/yt/visualization/volume_rendering/camera_path.py b/yt/visualization/volume_rendering/camera_path.py
index aeee7f940d9..eda7504e173 100644
--- a/yt/visualization/volume_rendering/camera_path.py
+++ b/yt/visualization/volume_rendering/camera_path.py
@@ -1,7 +1,10 @@
 import random
+
 import numpy as np
+
 from yt.visualization.volume_rendering.create_spline import create_spline
 
+
 class Keyframes:
     def __init__(self, x, y, z=None, north_vectors=None, up_vectors=None,
                  times=None, niter=50000, init_temp=10.0, alpha=0.999,
@@ -313,4 +316,3 @@ def write_path(self, filename="path.dat"):
                       self.path["up_vectors"][i,0], self.path["up_vectors"][i,1],
                       self.path["up_vectors"][i,2]))
         fp.close()
-
diff --git a/yt/visualization/volume_rendering/create_spline.py b/yt/visualization/volume_rendering/create_spline.py
index 7f7315892f4..22f8128578e 100644
--- a/yt/visualization/volume_rendering/create_spline.py
+++ b/yt/visualization/volume_rendering/create_spline.py
@@ -1,6 +1,8 @@
-import numpy as np
 import sys
 
+import numpy as np
+
+
 def create_spline(old_x, old_y, new_x, tension=0.5, sorted=False):
     """
 Inputs:
@@ -48,4 +50,3 @@ def create_spline(old_x, old_y, new_x, tension=0.5, sorted=False):
         result[i] = b0 * old_y[im2[i]] + b1 * old_y[im1[i]] + \
                     b2 * old_y[ind[i]] + b3 * old_y[ip1[i]]
     return result
-    
diff --git a/yt/visualization/volume_rendering/glfw_inputhook.py b/yt/visualization/volume_rendering/glfw_inputhook.py
index 52d37405b51..da4c4a6b6ec 100644
--- a/yt/visualization/volume_rendering/glfw_inputhook.py
+++ b/yt/visualization/volume_rendering/glfw_inputhook.py
@@ -27,6 +27,8 @@
 import sys
 import time
 
+from IPython.lib.inputhook import InputHookBase, inputhook_manager
+
 #-----------------------------------------------------------------------------
 # Platform-dependent imports and functions
 #-----------------------------------------------------------------------------
@@ -84,7 +86,6 @@ def inputhook_glfw():
         return 0
     return inputhook_glfw
 
-from IPython.lib.inputhook import inputhook_manager, InputHookBase
 
 @inputhook_manager.register('glfw')
 class GLFWInputHook(InputHookBase):
diff --git a/yt/visualization/volume_rendering/image_handling.py b/yt/visualization/volume_rendering/image_handling.py
index c9e9a5b7166..45c38b887d1 100644
--- a/yt/visualization/volume_rendering/image_handling.py
+++ b/yt/visualization/volume_rendering/image_handling.py
@@ -1,7 +1,8 @@
-from yt.utilities.on_demand_imports import _h5py as h5py
 import numpy as np
 
 from yt.funcs import mylog
+from yt.utilities.on_demand_imports import _h5py as h5py
+
 
 def export_rgba(image, fn, h5=True, fits=False, ):
     """
diff --git a/yt/visualization/volume_rendering/input_events.py b/yt/visualization/volume_rendering/input_events.py
index 541de61e5cc..6bf75d66e75 100644
--- a/yt/visualization/volume_rendering/input_events.py
+++ b/yt/visualization/volume_rendering/input_events.py
@@ -1,14 +1,14 @@
 # This is a part of the experimental Interactive Data Visualization
 
+import random
 from collections import defaultdict, namedtuple
-from yt.utilities.math_utils import \
-    get_perspective_matrix, \
-    get_orthographic_matrix
-import OpenGL.GL as GL
-import cyglfw3 as glfw
-import numpy as np
+
 import matplotlib.cm as cm
-import random
+import numpy as np
+
+import cyglfw3 as glfw
+import OpenGL.GL as GL
+from yt.utilities.math_utils import get_orthographic_matrix, get_perspective_matrix
 
 event_registry = {}
 
diff --git a/yt/visualization/volume_rendering/interactive_loop.py b/yt/visualization/volume_rendering/interactive_loop.py
index 8163b9c690e..1742e109150 100644
--- a/yt/visualization/volume_rendering/interactive_loop.py
+++ b/yt/visualization/volume_rendering/interactive_loop.py
@@ -2,12 +2,14 @@
 
 import os
 
-import cyglfw3 as glfw
 import numpy as np
+
+import cyglfw3 as glfw
 import OpenGL.GL as GL
+from yt import write_bitmap
+
 from .input_events import EventCollection, MouseRotation
 
-from yt import write_bitmap
 
 class EGLRenderingContext:
     '''Rendering context using EGL (experimental)
diff --git a/yt/visualization/volume_rendering/interactive_vr.py b/yt/visualization/volume_rendering/interactive_vr.py
index 95a09327902..dd65a16e227 100644
--- a/yt/visualization/volume_rendering/interactive_vr.py
+++ b/yt/visualization/volume_rendering/interactive_vr.py
@@ -1,23 +1,25 @@
 # This is a part of the experimental Interactive Data Visualization
 
-import OpenGL.GL as GL
+import ctypes
 from collections import OrderedDict
+
 import matplotlib.cm as cm
 import numpy as np
-import ctypes
 
-from yt.config import \
-    ytcfg
-from yt.utilities.math_utils import \
-    get_translate_matrix, \
-    get_scale_matrix, \
-    get_lookat_matrix, \
-    get_perspective_matrix, \
-    quaternion_mult, \
-    quaternion_to_rotation_matrix, \
-    rotation_matrix_to_quaternion
+import OpenGL.GL as GL
+from yt.config import ytcfg
 from yt.utilities.lib.mesh_triangulation import triangulate_mesh
-from .shader_objects import known_shaders, ShaderProgram
+from yt.utilities.math_utils import (
+    get_lookat_matrix,
+    get_perspective_matrix,
+    get_scale_matrix,
+    get_translate_matrix,
+    quaternion_mult,
+    quaternion_to_rotation_matrix,
+    rotation_matrix_to_quaternion,
+)
+
+from .shader_objects import ShaderProgram, known_shaders
 
 bbox_vertices = np.array(
       [[ 0.,  0.,  0.,  1.],
diff --git a/yt/visualization/volume_rendering/interactive_vr_helpers.py b/yt/visualization/volume_rendering/interactive_vr_helpers.py
index f2985d46207..6cce1766680 100644
--- a/yt/visualization/volume_rendering/interactive_vr_helpers.py
+++ b/yt/visualization/volume_rendering/interactive_vr_helpers.py
@@ -1,10 +1,12 @@
 # This part of the experimental Interactive Data Visualization
 
 import numpy as np
-from yt.funcs import mylog
+
 from yt.data_objects.static_output import Dataset
+from yt.funcs import mylog
 from yt.utilities.exceptions import YTSceneFieldNotFound
 
+
 def _render_opengl(data_source, field=None, window_size=None, cam_position=None,
                    cam_focus=None):
     '''High level wrapper for Interactive Data Visualization
diff --git a/yt/visualization/volume_rendering/lens.py b/yt/visualization/volume_rendering/lens.py
index 1d9de3a1ad2..a074f6f8a16 100644
--- a/yt/visualization/volume_rendering/lens.py
+++ b/yt/visualization/volume_rendering/lens.py
@@ -1,13 +1,13 @@
-from yt.funcs import mylog
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    ParallelAnalysisInterface
-from yt.data_objects.image_array import ImageArray
-from yt.units.yt_array import unorm, uvstack, uhstack
-from yt.utilities.math_utils import get_rotation_matrix
 import numpy as np
 
-from yt.utilities.lib.grid_traversal import \
-    arr_fisheye_vectors
+from yt.data_objects.image_array import ImageArray
+from yt.funcs import mylog
+from yt.units.yt_array import uhstack, unorm, uvstack
+from yt.utilities.lib.grid_traversal import arr_fisheye_vectors
+from yt.utilities.math_utils import get_rotation_matrix
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    ParallelAnalysisInterface,
+)
 
 
 class Lens(ParallelAnalysisInterface):
diff --git a/yt/visualization/volume_rendering/off_axis_projection.py b/yt/visualization/volume_rendering/off_axis_projection.py
index 8327579f04c..501fd828404 100644
--- a/yt/visualization/volume_rendering/off_axis_projection.py
+++ b/yt/visualization/volume_rendering/off_axis_projection.py
@@ -1,17 +1,19 @@
 
-from .scene import Scene
+import numpy as np
+
+from yt.data_objects.api import ImageArray
+from yt.funcs import iterable, mylog
+from yt.units.unit_object import Unit
+from yt.utilities.lib.partitioned_grid import PartitionedGrid
+from yt.utilities.lib.pixelization_routines import (
+    normalization_2d_utility,
+    off_axis_projection_SPH,
+)
+
 from .render_source import VolumeSource
+from .scene import Scene
 from .transfer_functions import ProjectionTransferFunction
 from .utils import data_source_or_all
-from yt.funcs import mylog, iterable
-from yt.utilities.lib.partitioned_grid import \
-    PartitionedGrid
-from yt.units.unit_object import Unit
-from yt.data_objects.api import ImageArray
-from yt.utilities.lib.pixelization_routines import \
-    off_axis_projection_SPH, \
-    normalization_2d_utility
-import numpy as np
 
 
 def off_axis_projection(data_source, center, normal_vector,
diff --git a/yt/visualization/volume_rendering/old_camera.py b/yt/visualization/volume_rendering/old_camera.py
index eb92cf4f865..01c84613d1e 100644
--- a/yt/visualization/volume_rendering/old_camera.py
+++ b/yt/visualization/volume_rendering/old_camera.py
@@ -1,37 +1,40 @@
 import builtins
-import numpy as np
-
-from yt.config import \
-    ytcfg
-from yt.funcs import \
-    iterable, mylog, get_pbar, \
-    get_num_threads, ensure_numpy_array
-from yt.units.yt_array import YTArray
-from yt.utilities.exceptions import YTNotInsideNotebook
 from copy import deepcopy
 
-from .transfer_functions import ProjectionTransferFunction
-
-from yt.utilities.lib.grid_traversal import \
-    pixelize_healpix, arr_fisheye_vectors, arr_pix2vec_nest
-from yt.utilities.lib.partitioned_grid import \
-    PartitionedGrid
-from yt.utilities.lib.image_samplers import \
-    ProjectionSampler, VolumeRenderSampler, \
-    LightSourceRenderSampler, InterpolatedProjectionSampler
-from yt.utilities.lib.misc_utilities import \
-    lines
+import numpy as np
 
-from yt.utilities.math_utils import get_rotation_matrix
-from yt.utilities.orientation import Orientation
+from yt.config import ytcfg
 from yt.data_objects.api import ImageArray
-from yt.visualization.image_writer import write_bitmap, write_image, apply_colormap
 from yt.data_objects.data_containers import data_object_registry
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    ParallelAnalysisInterface, parallel_objects
+from yt.funcs import ensure_numpy_array, get_num_threads, get_pbar, iterable, mylog
+from yt.units.yt_array import YTArray
 from yt.utilities.amr_kdtree.api import AMRKDTree
+from yt.utilities.exceptions import YTNotInsideNotebook
+from yt.utilities.lib.grid_traversal import (
+    arr_fisheye_vectors,
+    arr_pix2vec_nest,
+    pixelize_healpix,
+)
+from yt.utilities.lib.image_samplers import (
+    InterpolatedProjectionSampler,
+    LightSourceRenderSampler,
+    ProjectionSampler,
+    VolumeRenderSampler,
+)
+from yt.utilities.lib.misc_utilities import lines
+from yt.utilities.lib.partitioned_grid import PartitionedGrid
+from yt.utilities.math_utils import get_rotation_matrix
+from yt.utilities.orientation import Orientation
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    ParallelAnalysisInterface,
+    parallel_objects,
+)
+from yt.visualization.image_writer import apply_colormap, write_bitmap, write_image
 from yt.visualization.volume_rendering.blenders import enhance_rgba
 
+from .transfer_functions import ProjectionTransferFunction
+
+
 def get_corners(le, re):
     return np.array([
       [le[0], le[1], le[2]],
@@ -2207,4 +2210,3 @@ def off_axis_projection(ds, center, normal_vector, width, resolution,
                                north_vector=north_vector, method=method)
     image = projcam.snapshot()
     return image[:,:]
-
diff --git a/yt/visualization/volume_rendering/render_source.py b/yt/visualization/volume_rendering/render_source.py
index de7a6277944..91c4564dd59 100644
--- a/yt/visualization/volume_rendering/render_source.py
+++ b/yt/visualization/volume_rendering/render_source.py
@@ -1,25 +1,35 @@
-import numpy as np
 from functools import wraps
-from yt.config import \
-    ytcfg
-from yt.funcs import mylog, ensure_numpy_array, iterable
-from yt.utilities.parallel_tools.parallel_analysis_interface import \
-    ParallelAnalysisInterface
+
+import numpy as np
+
+from yt.config import ytcfg
+from yt.data_objects.image_array import ImageArray
+from yt.funcs import ensure_numpy_array, iterable, mylog
 from yt.utilities.amr_kdtree.api import AMRKDTree
-from .transfer_function_helper import TransferFunctionHelper
-from .transfer_functions import TransferFunction, \
-    ProjectionTransferFunction, ColorTransferFunction
-from .utils import new_volume_render_sampler, data_source_or_all, \
-    get_corners, new_projection_sampler, new_mesh_sampler, \
-    new_interpolated_projection_sampler
 from yt.utilities.lib.bounding_volume_hierarchy import BVH
+from yt.utilities.lib.misc_utilities import zlines, zpoints
+from yt.utilities.on_demand_imports import NotAModule
+from yt.utilities.parallel_tools.parallel_analysis_interface import (
+    ParallelAnalysisInterface,
+)
 from yt.visualization.image_writer import apply_colormap
-from yt.data_objects.image_array import ImageArray
+
+from .transfer_function_helper import TransferFunctionHelper
+from .transfer_functions import (
+    ColorTransferFunction,
+    ProjectionTransferFunction,
+    TransferFunction,
+)
+from .utils import (
+    data_source_or_all,
+    get_corners,
+    new_interpolated_projection_sampler,
+    new_mesh_sampler,
+    new_projection_sampler,
+    new_volume_render_sampler,
+)
 from .zbuffer_array import ZBuffer
-from yt.utilities.lib.misc_utilities import \
-    zlines, zpoints
 
-from yt.utilities.on_demand_imports import NotAModule
 try:
     from yt.utilities.lib import mesh_traversal
 # Catch ValueError in case size of objects in Cython change
diff --git a/yt/visualization/volume_rendering/scene.py b/yt/visualization/volume_rendering/scene.py
index 35597e973db..aba1cae949e 100644
--- a/yt/visualization/volume_rendering/scene.py
+++ b/yt/visualization/volume_rendering/scene.py
@@ -1,31 +1,31 @@
 
+import builtins
 import functools
-import numpy as np
 from collections import OrderedDict
-from yt.config import \
-    ytcfg
-from yt.funcs import mylog, get_image_suffix
-from yt.units.dimensions import \
-    length
-from yt.units.unit_registry import \
-    UnitRegistry
-from yt.units.yt_array import \
-    YTQuantity, \
-    YTArray
+
+import numpy as np
+
+from yt.config import ytcfg
+from yt.funcs import get_image_suffix, mylog
+from yt.units.dimensions import length
+from yt.units.unit_registry import UnitRegistry
+from yt.units.yt_array import YTArray, YTQuantity
+from yt.utilities.exceptions import YTNotInsideNotebook
+
 from .camera import Camera
-from .render_source import \
-    OpaqueSource, \
-    BoxSource, \
-    CoordinateVectorSource, \
-    GridSource, \
-    RenderSource, \
-    MeshSource, \
-    VolumeSource, \
-    PointSource, \
-    LineSource
+from .render_source import (
+    BoxSource,
+    CoordinateVectorSource,
+    GridSource,
+    LineSource,
+    MeshSource,
+    OpaqueSource,
+    PointSource,
+    RenderSource,
+    VolumeSource,
+)
 from .zbuffer_array import ZBuffer
-import builtins
-from yt.utilities.exceptions import YTNotInsideNotebook
+
 
 class Scene:
 
diff --git a/yt/visualization/volume_rendering/shader_objects.py b/yt/visualization/volume_rendering/shader_objects.py
index 0ce6fa736a0..f50d61c519c 100644
--- a/yt/visualization/volume_rendering/shader_objects.py
+++ b/yt/visualization/volume_rendering/shader_objects.py
@@ -1,14 +1,16 @@
 # This is a part of the experimental Interactive Data Visualization 
 
-import os
-import OpenGL.GL as GL
 import contextlib
+import os
 from collections import OrderedDict
-from yt.utilities.exceptions import \
-    YTInvalidShaderType, \
-    YTUnknownUniformKind, \
-    YTUnknownUniformSize
+
+import OpenGL.GL as GL
 from yt.units.yt_array import YTQuantity
+from yt.utilities.exceptions import (
+    YTInvalidShaderType,
+    YTUnknownUniformKind,
+    YTUnknownUniformSize,
+)
 
 known_shaders = {}
 
diff --git a/yt/visualization/volume_rendering/tests/test_camera_attributes.py b/yt/visualization/volume_rendering/tests/test_camera_attributes.py
index 3c12e504a29..c4ffc6b8385 100644
--- a/yt/visualization/volume_rendering/tests/test_camera_attributes.py
+++ b/yt/visualization/volume_rendering/tests/test_camera_attributes.py
@@ -1,13 +1,8 @@
 import numpy as np
-import yt.units as u
-
-from yt.testing import \
-    assert_almost_equal, \
-    assert_equal, \
-    fake_random_ds
-from yt.visualization.volume_rendering.api import \
-    Scene
 
+import yt.units as u
+from yt.testing import assert_almost_equal, assert_equal, fake_random_ds
+from yt.visualization.volume_rendering.api import Scene
 
 valid_lens_types = [
     'plane-parallel',
diff --git a/yt/visualization/volume_rendering/tests/test_composite.py b/yt/visualization/volume_rendering/tests/test_composite.py
index 2f673565d79..98167295224 100644
--- a/yt/visualization/volume_rendering/tests/test_composite.py
+++ b/yt/visualization/volume_rendering/tests/test_composite.py
@@ -1,16 +1,19 @@
 import os
-import tempfile
 import shutil
-from yt.testing import fake_random_ds
-from yt.visualization.volume_rendering.api import \
-    Scene, \
-    VolumeSource, \
-    LineSource, \
-    BoxSource
-from yt.data_objects.api import ImageArray
-import numpy as np
+import tempfile
 from unittest import TestCase
 
+import numpy as np
+
+from yt.data_objects.api import ImageArray
+from yt.testing import fake_random_ds
+from yt.visualization.volume_rendering.api import (
+    BoxSource,
+    LineSource,
+    Scene,
+    VolumeSource,
+)
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/volume_rendering/tests/test_lenses.py b/yt/visualization/volume_rendering/tests/test_lenses.py
index 35719147247..62a001a208a 100644
--- a/yt/visualization/volume_rendering/tests/test_lenses.py
+++ b/yt/visualization/volume_rendering/tests/test_lenses.py
@@ -1,10 +1,13 @@
 import os
-import tempfile
 import shutil
+import tempfile
+from unittest import TestCase
+
+import numpy as np
+
 from yt.testing import fake_random_ds
 from yt.visualization.volume_rendering.api import Scene, VolumeSource
-import numpy as np
-from unittest import TestCase
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/volume_rendering/tests/test_mesh_render.py b/yt/visualization/volume_rendering/tests/test_mesh_render.py
index e3885b75dc2..a139ce05268 100644
--- a/yt/visualization/volume_rendering/tests/test_mesh_render.py
+++ b/yt/visualization/volume_rendering/tests/test_mesh_render.py
@@ -1,18 +1,19 @@
 from nose.plugins.attrib import attr
-from yt.testing import \
-    fake_tetrahedral_ds, \
-    fake_hexahedral_ds, \
-    requires_module, ANSWER_TEST_TAG
-from yt.utilities.answer_testing.framework import \
-    requires_ds, \
-    data_dir_load, \
-    GenericImageTest
-from yt.visualization.volume_rendering.api import \
-    MeshSource, \
-    Scene, \
-    create_scene
-from yt.config import \
-    ytcfg
+
+from yt.config import ytcfg
+from yt.testing import (
+    ANSWER_TEST_TAG,
+    fake_hexahedral_ds,
+    fake_tetrahedral_ds,
+    requires_module,
+)
+from yt.utilities.answer_testing.framework import (
+    GenericImageTest,
+    data_dir_load,
+    requires_ds,
+)
+from yt.visualization.volume_rendering.api import MeshSource, Scene, create_scene
+
 
 def compare(ds, im, test_prefix, test_name=None, decimals=12):
     def mesh_render_image_func(filename_prefix):
diff --git a/yt/visualization/volume_rendering/tests/test_off_axis_SPH.py b/yt/visualization/volume_rendering/tests/test_off_axis_SPH.py
index 62df69a66b7..5dcd9ed66d1 100644
--- a/yt/visualization/volume_rendering/tests/test_off_axis_SPH.py
+++ b/yt/visualization/volume_rendering/tests/test_off_axis_SPH.py
@@ -1,13 +1,9 @@
-from yt.visualization.volume_rendering import \
-    off_axis_projection as OffAP
-from yt.testing import \
-    fake_sph_orientation_ds, \
-    assert_almost_equal, \
-    requires_module
-from yt.utilities.lib.pixelization_routines import \
-    pixelize_sph_kernel_projection
 import numpy as np
+
+from yt.testing import assert_almost_equal, fake_sph_orientation_ds, requires_module
+from yt.utilities.lib.pixelization_routines import pixelize_sph_kernel_projection
 from yt.utilities.on_demand_imports import _scipy
+from yt.visualization.volume_rendering import off_axis_projection as OffAP
 
 spatial = _scipy.spatial
 ndimage = _scipy.ndimage
diff --git a/yt/visualization/volume_rendering/tests/test_points.py b/yt/visualization/volume_rendering/tests/test_points.py
index c81744ad2dc..05b7d1099e6 100644
--- a/yt/visualization/volume_rendering/tests/test_points.py
+++ b/yt/visualization/volume_rendering/tests/test_points.py
@@ -1,14 +1,13 @@
 import os
-import tempfile
 import shutil
-from yt.testing import fake_random_ds
-from yt.visualization.volume_rendering.api import \
-    Scene, \
-    VolumeSource, \
-    PointSource
-import numpy as np
+import tempfile
 from unittest import TestCase
 
+import numpy as np
+
+from yt.testing import fake_random_ds
+from yt.visualization.volume_rendering.api import PointSource, Scene, VolumeSource
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/volume_rendering/tests/test_scene.py b/yt/visualization/volume_rendering/tests/test_scene.py
index 8228a8c0f7b..5ad52c068f0 100644
--- a/yt/visualization/volume_rendering/tests/test_scene.py
+++ b/yt/visualization/volume_rendering/tests/test_scene.py
@@ -1,17 +1,17 @@
 import os
-import tempfile
 import shutil
-from yt.testing import \
-    fake_random_ds, \
-    assert_fname, \
-    fake_vr_orientation_test_ds
-from yt.visualization.volume_rendering.api import \
-    create_scene, \
-    volume_render, \
-    VolumeSource
-import numpy as np
+import tempfile
 from unittest import TestCase
 
+import numpy as np
+
+from yt.testing import assert_fname, fake_random_ds, fake_vr_orientation_test_ds
+from yt.visualization.volume_rendering.api import (
+    VolumeSource,
+    create_scene,
+    volume_render,
+)
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/volume_rendering/tests/test_sigma_clip.py b/yt/visualization/volume_rendering/tests/test_sigma_clip.py
index 99cb1b9cb02..ceac5046511 100644
--- a/yt/visualization/volume_rendering/tests/test_sigma_clip.py
+++ b/yt/visualization/volume_rendering/tests/test_sigma_clip.py
@@ -1,9 +1,11 @@
 import os
-import tempfile
 import shutil
+import tempfile
+from unittest import TestCase
+
 import yt
 from yt.testing import fake_random_ds
-from unittest import TestCase
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/volume_rendering/tests/test_simple_vr.py b/yt/visualization/volume_rendering/tests/test_simple_vr.py
index 319b36f279c..7e733612af9 100644
--- a/yt/visualization/volume_rendering/tests/test_simple_vr.py
+++ b/yt/visualization/volume_rendering/tests/test_simple_vr.py
@@ -1,9 +1,10 @@
 import os
-import tempfile
 import shutil
+import tempfile
+from unittest import TestCase
+
 import yt
 from yt.testing import fake_random_ds
-from unittest import TestCase
 
 
 def setup():
diff --git a/yt/visualization/volume_rendering/tests/test_varia.py b/yt/visualization/volume_rendering/tests/test_varia.py
index 2d75926a34c..9bdfdb0a533 100644
--- a/yt/visualization/volume_rendering/tests/test_varia.py
+++ b/yt/visualization/volume_rendering/tests/test_varia.py
@@ -1,14 +1,15 @@
 import os
-import tempfile
 import shutil
+import tempfile
+from unittest import TestCase
+
 import numpy as np
 
 import yt
-from yt.testing import \
-    fake_random_ds
+from yt.testing import fake_random_ds
 from yt.visualization.volume_rendering.render_source import VolumeSource
 from yt.visualization.volume_rendering.scene import Scene
-from unittest import TestCase
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/volume_rendering/tests/test_vr_cameras.py b/yt/visualization/volume_rendering/tests/test_vr_cameras.py
index fc7992cf970..74e59dba5c9 100644
--- a/yt/visualization/volume_rendering/tests/test_vr_cameras.py
+++ b/yt/visualization/volume_rendering/tests/test_vr_cameras.py
@@ -1,18 +1,24 @@
 import os
 import os.path
-import tempfile
 import shutil
-from yt.testing import \
-    fake_random_ds, \
-    assert_fname
-import numpy as np
-from yt.visualization.volume_rendering.old_camera import \
-    PerspectiveCamera, StereoPairCamera, InteractiveCamera, ProjectionCamera, \
-    FisheyeCamera
-from yt.visualization.volume_rendering.api import ColorTransferFunction, \
-    ProjectionTransferFunction
+import tempfile
 from unittest import TestCase
 
+import numpy as np
+
+from yt.testing import assert_fname, fake_random_ds
+from yt.visualization.volume_rendering.api import (
+    ColorTransferFunction,
+    ProjectionTransferFunction,
+)
+from yt.visualization.volume_rendering.old_camera import (
+    FisheyeCamera,
+    InteractiveCamera,
+    PerspectiveCamera,
+    ProjectionCamera,
+    StereoPairCamera,
+)
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/volume_rendering/tests/test_vr_orientation.py b/yt/visualization/volume_rendering/tests/test_vr_orientation.py
index c6e923f6437..95ef45ea518 100644
--- a/yt/visualization/volume_rendering/tests/test_vr_orientation.py
+++ b/yt/visualization/volume_rendering/tests/test_vr_orientation.py
@@ -1,15 +1,18 @@
 
 import numpy as np
 from nose.plugins.attrib import attr
+
 from yt.testing import ANSWER_TEST_TAG, fake_vr_orientation_test_ds
-from yt.utilities.answer_testing.framework import \
-    VRImageComparisonTest, \
-    GenericImageTest
-from yt.visualization.volume_rendering.api import \
-    Scene, \
-    VolumeSource, \
-    ColorTransferFunction, \
-    off_axis_projection
+from yt.utilities.answer_testing.framework import (
+    GenericImageTest,
+    VRImageComparisonTest,
+)
+from yt.visualization.volume_rendering.api import (
+    ColorTransferFunction,
+    Scene,
+    VolumeSource,
+    off_axis_projection,
+)
 
 
 @attr(ANSWER_TEST_TAG)
diff --git a/yt/visualization/volume_rendering/tests/test_zbuff.py b/yt/visualization/volume_rendering/tests/test_zbuff.py
index c51cc698348..35b1da152d5 100644
--- a/yt/visualization/volume_rendering/tests/test_zbuff.py
+++ b/yt/visualization/volume_rendering/tests/test_zbuff.py
@@ -1,16 +1,18 @@
 import os
-import tempfile
 import shutil
-from yt.testing import fake_random_ds
-from yt.visualization.volume_rendering.api import \
-    Scene, \
-    ZBuffer, \
-    VolumeSource, \
-    OpaqueSource
-from yt.testing import assert_almost_equal
-import numpy as np
+import tempfile
 from unittest import TestCase
 
+import numpy as np
+
+from yt.testing import assert_almost_equal, fake_random_ds
+from yt.visualization.volume_rendering.api import (
+    OpaqueSource,
+    Scene,
+    VolumeSource,
+    ZBuffer,
+)
+
 
 def setup():
     """Test specific setup."""
diff --git a/yt/visualization/volume_rendering/transfer_function_helper.py b/yt/visualization/volume_rendering/transfer_function_helper.py
index 78504e4682d..e04614480f2 100644
--- a/yt/visualization/volume_rendering/transfer_function_helper.py
+++ b/yt/visualization/volume_rendering/transfer_function_helper.py
@@ -1,13 +1,12 @@
+from distutils.version import LooseVersion
+from io import BytesIO
+
 import matplotlib
 import numpy as np
 
-from distutils.version import LooseVersion
-
-from yt.funcs import mylog
 from yt.data_objects.profiles import create_profile
-from yt.visualization.volume_rendering.transfer_functions import \
-    ColorTransferFunction
-from io import BytesIO
+from yt.funcs import mylog
+from yt.visualization.volume_rendering.transfer_functions import ColorTransferFunction
 
 
 class TransferFunctionHelper:
diff --git a/yt/visualization/volume_rendering/transfer_functions.py b/yt/visualization/volume_rendering/transfer_functions.py
index 64e280cf1b8..2752a1a00c2 100644
--- a/yt/visualization/volume_rendering/transfer_functions.py
+++ b/yt/visualization/volume_rendering/transfer_functions.py
@@ -1,11 +1,9 @@
 import numpy as np
 from matplotlib.cm import get_cmap
 
-from yt.funcs import \
-    mylog, ensure_list
+from yt.funcs import ensure_list, mylog
+from yt.utilities.physical_constants import clight, hcgs, kboltz
 
-from yt.utilities.physical_constants import \
-    clight, hcgs, kboltz
 
 class TransferFunction:
     r"""A transfer function governs the transmission of emission and
diff --git a/yt/visualization/volume_rendering/utils.py b/yt/visualization/volume_rendering/utils.py
index 29ea21e0818..f57348dd911 100644
--- a/yt/visualization/volume_rendering/utils.py
+++ b/yt/visualization/volume_rendering/utils.py
@@ -1,12 +1,15 @@
 import numpy as np
-from yt.data_objects.data_containers import \
-    YTSelectionContainer3D
+
+from yt.data_objects.data_containers import YTSelectionContainer3D
 from yt.data_objects.static_output import Dataset
 from yt.utilities.lib import bounding_volume_hierarchy
-from yt.utilities.lib.image_samplers import \
-    VolumeRenderSampler, InterpolatedProjectionSampler, ProjectionSampler
-
+from yt.utilities.lib.image_samplers import (
+    InterpolatedProjectionSampler,
+    ProjectionSampler,
+    VolumeRenderSampler,
+)
 from yt.utilities.on_demand_imports import NotAModule
+
 try:
     from yt.utilities.lib import mesh_traversal
 # Catch ValueError in case size of objects in Cython change
@@ -143,4 +146,3 @@ def ensure_code_unit_params(params):
     if hasattr(bounds[0], 'units'):
         params['bounds'] = tuple(b.in_units('code_length').d for b in bounds)
     return params
-
diff --git a/yt/visualization/volume_rendering/volume_rendering.py b/yt/visualization/volume_rendering/volume_rendering.py
index b91d1e4a672..4af759e0f6c 100644
--- a/yt/visualization/volume_rendering/volume_rendering.py
+++ b/yt/visualization/volume_rendering/volume_rendering.py
@@ -1,11 +1,11 @@
 
-from .scene import Scene
-from .render_source import VolumeSource, \
-    MeshSource
-from .utils import data_source_or_all
 from yt.funcs import mylog
 from yt.utilities.exceptions import YTSceneFieldNotFound
 
+from .render_source import MeshSource, VolumeSource
+from .scene import Scene
+from .utils import data_source_or_all
+
 
 def create_scene(data_source, field=None, lens_type='plane-parallel'):
     r""" Set up a scene object with sensible defaults for use in volume