diff --git a/.github/workflows/lint_python.yml b/.github/workflows/lint_python.yml
index b4ea755..8050a26 100644
--- a/.github/workflows/lint_python.yml
+++ b/.github/workflows/lint_python.yml
@@ -24,6 +24,7 @@ jobs:
         python -m pip install --upgrade pip
         pip install -r requirements.txt
         pip install -r test-requirements.txt
+        pip install -e .
 
-    - run: flake8 sruthi --count --show-source --statistics
+    - run: flake8 . --count --show-source --statistics
     - run: pytest
diff --git a/setup.cfg b/setup.cfg
new file mode 100644
index 0000000..aec1659
--- /dev/null
+++ b/setup.cfg
@@ -0,0 +1,2 @@
+[flake8]
+max-complexity = 10
diff --git a/sruthi/__init__.py b/sruthi/__init__.py
index 92e6642..87af0a1 100644
--- a/sruthi/__init__.py
+++ b/sruthi/__init__.py
@@ -1,4 +1,4 @@
 __version__ = '0.0.1'
 
-from .errors import (SruthiError, ServerIncompatibleError, SruError, NoMoreRecordsError)
-from .sru import searchretrieve, explain
+from .errors import (SruthiError, ServerIncompatibleError, SruError, NoMoreRecordsError)   # noqa
+from .sru import searchretrieve, explain  # noqa
diff --git a/sruthi/client.py b/sruthi/client.py
index bdeba86..456cd5f 100644
--- a/sruthi/client.py
+++ b/sruthi/client.py
@@ -5,6 +5,7 @@
 from . import xmlparse
 from . import metadata
 
+
 class Client(object):
     def __init__(self, url=None, page_size=100):
         self.session = requests.Session()
@@ -34,7 +35,6 @@ def explain(self):
         params = {
             'operation': 'explain',
             'version': '1.2',
-            'query': query,
         }
         content = self._get_content(self.url, params)
         return content
@@ -101,9 +101,14 @@ def _get_content(self, url, params):
     def _check_errors(self, xml):
         config = self.OPERATIONS[self.operation]
         if not xml.tag == config['response']:
-            raise errors.ServerIncompatibleError('Server response did not contain a searchRetrieveResponse tag')
+            raise errors.ServerIncompatibleError(
+                'Server response did not contain a searchRetrieveResponse tag'
+            )
 
-        diagnostics = xmlparse.find(xml, '%sdiagnostics/%sdiagnostic' % (self.sru, self.sru))
+        diagnostics = xmlparse.find(
+            xml,
+            f'{self.sru}diagnostics/{self.sru}diagnostic'
+        )
         if diagnostics:
-           error_msg = " ".join([d.find(detail).text for d in diagnostics])
-           raise errors.SruError(error_msg)
+            error_msg = " ".join([d.find('detail').text for d in diagnostics])
+            raise errors.SruError(error_msg)
diff --git a/sruthi/errors.py b/sruthi/errors.py
index 7925b82..266834a 100644
--- a/sruthi/errors.py
+++ b/sruthi/errors.py
@@ -3,18 +3,23 @@ class SruthiError(Exception):
     General sruthi error class to provide a superclass for all other errors
     """
 
+
 class ServerIncompatibleError(SruthiError):
     """
     The error raised from sru.search/sru.explain when the server doesn't behave
     like a SRU endpoint.
     """
 
+
 class SruError(SruthiError):
     """
-    The error raised from sru.search/sru.explain when the SRU response contains an error
+    The error raised from sru.search/sru.explain when the SRU response contains
+    an error
     """
 
+
 class NoMoreRecordsError(SruthiError):
     """
-    This error is raised if all records have been loaded (or no records are present)
+    This error is raised if all records have been loaded (or no records are
+    present)
     """
diff --git a/sruthi/metadata.py b/sruthi/metadata.py
index 1a5974d..e19cb25 100644
--- a/sruthi/metadata.py
+++ b/sruthi/metadata.py
@@ -5,13 +5,14 @@
 from . import xmlparse
 from . import errors
 
+
 class SruData(object):
-    def __init__(self, records=[], sru_version=None, count=0, data_loader=None):
+    def __init__(self, records=[], sru_version=None, count=0, data_loader=None):  # noqa
         self.records = records
         self.sru_version = sru_version
         self.count = count
         self._data_loader = data_loader
-    
+
     def __repr__(self):
         return (
             'SruData('
@@ -29,7 +30,7 @@ def __length_hint__(self):
 
     def __iter__(self):
         # use while loop since self.records could grow while iterating
-        i = 0 
+        i = 0
         while True:
             # load new data when near end
             if i == len(self.records):
@@ -38,38 +39,32 @@ def __iter__(self):
                 except errors.NoMoreRecordsError:
                     break
             yield self.records[i]
-            i += 1  
+            i += 1
 
     def __getitem__(self, key):
         if isinstance(key, slice):
             limit = max(key.start or 0, key.stop or self.count)
-            while limit > len(self.records):
-                try:
-                    self._load_new_data()
-                except errors.NoMoreRecordsError:
-                    pass
-            return [self.records[k] for k in range(*key.indices(len(self.records)))]
+            self._load_new_data_until(limit)
+            count = len(self.records)
+            return [self.records[k] for k in range(*key.indices(count))]
+
         if not isinstance(key, int):
-            raise IndexError("Index must be an integer")
-        if key >= self.count:
-            raise IndexError("Index %s is out of range" % key)
-        if key < 0:
-            # load all data
-            while True:
-                try:
-                    self._load_new_data()
-                except errors.NoMoreRecordsError:
-                    break
-        else:
-            while key >= len(self.records):
-                try:
-                    self._load_new_data()
-                except errors.NoMoreRecordsError:
-                    if key >= len(self.records):
-                        raise IndexError("Index %s not found" % key)
+            raise TypeError("Index must be an integer or slice")
 
+        limit = key
+        if limit < 0:
+            # if we get a negative index, load all data
+            limit = self.count
+        self._load_new_data_until(limit)
         return self.records[key]
 
+    def _load_new_data_until(self, limit):
+        while limit >= len(self.records):
+            try:
+                self._load_new_data()
+            except errors.NoMoreRecordsError:
+                break
+
     def _load_new_data(self):
         result = self._data_loader()
         self.records.extend(result['records'])
@@ -84,7 +79,7 @@ def extract_records(xml):
         record['schema'] = xmlparse.find(xml_rec, './sru:recordSchema').text
         record_data = xmlparse.find(xml_rec, './sru:recordData')
         extra_data = xmlparse.find(xml_rec, './sru:extraRecordData')
-        
+
         for elem in record_data.iter():
             record = tag_data(record, elem)
 
@@ -106,6 +101,6 @@ def tag_data(record, elem):
     tag_name = ns_pattern.sub('', elem.tag)
     if elem.text and elem.text.strip():
         record[tag_name] = elem.text.strip()
-    elif len(list(elem)) == 0: # leaf element
+    elif len(list(elem)) == 0:  # leaf element
         record[tag_name] = None
     return record
diff --git a/sruthi/sru.py b/sruthi/sru.py
index 26d5d13..9210a02 100644
--- a/sruthi/sru.py
+++ b/sruthi/sru.py
@@ -2,10 +2,12 @@
 
 from . import client
 
+
 def searchretrieve(url, query):
     c = client.Client(url)
     return c.searchretrieve(query)
 
+
 def explain(url):
     c = client.Client(url)
     return c.explain()
diff --git a/sruthi/xmlparse.py b/sruthi/xmlparse.py
index 97a81f5..7f27a1d 100644
--- a/sruthi/xmlparse.py
+++ b/sruthi/xmlparse.py
@@ -8,6 +8,7 @@
     'ap': 'http://www.archivportal.ch/srw/extension/',
 }
 
+
 class XMLNone(object):
     def __nonzero__(self):
         return False
diff --git a/tests/client_test.py b/tests/client_test.py
index 802249e..f983e4a 100644
--- a/tests/client_test.py
+++ b/tests/client_test.py
@@ -18,8 +18,16 @@ def test_searchretrieve(self, session_mock):
         for rec in r:
             self.assertIsInstance(rec, dict)
             self.assertEqual(rec['schema'], 'isad')
-        
-        session_mock.return_value.get.assert_any_call('http://test.com/sru', params={'startRecord': 1, 'query': 'Test-Query', 'operation': 'searchretrieve', 'version': '1.2'})
+
+        session_mock.return_value.get.assert_any_call(
+            'http://test.com/sru',
+            params={
+                'startRecord': 1,
+                'query': 'Test-Query',
+                'operation': 'searchretrieve',
+                'version': '1.2'
+            }
+        )
 
 # add test for getitem with slices etc.
 # print("-3")
diff --git a/tests/sru_test.py b/tests/sru_test.py
index d1122c3..b905a51 100644
--- a/tests/sru_test.py
+++ b/tests/sru_test.py
@@ -21,15 +21,15 @@ def test_searchretrieve(self, session_mock):
                 'reference': 'VII.335.:2.34.8.',
                 'extra': {
                     'score': '0.38',
-                    'link': 'https://amsquery.stadt-zuerich.ch/detail.aspx?Id=410130',
+                    'link': 'https://amsquery.stadt-zuerich.ch/detail.aspx?Id=410130',  # noqa
                     'hasDigitizedItems': '0',
                     'endDateISO': '1998-12-31',
-                    'beginDateISO': '1998-01-01', 
+                    'beginDateISO': '1998-01-01',
                     'beginApprox': '0',
                     'endApprox': '0'
                 },
                 'descriptionlevel': 'Dossier',
-                'title': u'Podium "Frauen und Politik" beim Jubil\xe4umsanlass "Frauenrechte-Menschenrechte" des Bundes Schweizerischer Frauenorganisationen BSF zu 150 Jahre Bundesstaat, 50 Jahre UNO-Menschenrechtserkl\xe4rung und 27 Jahre politische Gleichberechtigung im Nationalratssaal in Bern vom 4. April 1998',
+                'title': u'Podium "Frauen und Politik" beim Jubil\xe4umsanlass "Frauenrechte-Menschenrechte" des Bundes Schweizerischer Frauenorganisationen BSF zu 150 Jahre Bundesstaat, 50 Jahre UNO-Menschenrechtserkl\xe4rung und 27 Jahre politische Gleichberechtigung im Nationalratssaal in Bern vom 4. April 1998',  # noqa
                 'extent': None,
                 'date': '1998',
                 'creator': None,
diff --git a/tests/sruthi_test.py b/tests/sruthi_test.py
index 7fe058a..66b3f28 100644
--- a/tests/sruthi_test.py
+++ b/tests/sruthi_test.py
@@ -20,5 +20,4 @@ def _session_mock(self, session_mock, filename=None):
             filename
         )
         with open(path) as file:
-            session_mock.return_value.get.return_value = mock.MagicMock(content=file.read())
-
+            session_mock.return_value.get.return_value = mock.MagicMock(content=file.read())  # noqa