diff --git a/unyt/_array_functions.py b/unyt/_array_functions.py
index 44738ba3..8ea16c2b 100644
--- a/unyt/_array_functions.py
+++ b/unyt/_array_functions.py
@@ -202,7 +202,9 @@ def histogram2d(x, y, bins=10, range=None, density=None, weights=None, *args, **
 
 
 @implements(np.histogramdd)
-def histogramdd(sample, bins=10, range=None, density=None, weights=None, *args, **kwargs):
+def histogramdd(
+    sample, bins=10, range=None, density=None, weights=None, *args, **kwargs
+):
     units = [_.units for _ in sample]
     range = _sanitize_range(range, units=units)
     counts, bins = np.histogramdd._implementation(
diff --git a/unyt/tests/test_array_functions.py b/unyt/tests/test_array_functions.py
index 6fe3585c..6d75638d 100644
--- a/unyt/tests/test_array_functions.py
+++ b/unyt/tests/test_array_functions.py
@@ -667,15 +667,15 @@ def test_histogram_with_weights_density():
     # check case with density
     rng = np.random.default_rng()
     arr = rng.normal(size=1000) * cm
-    density, bins = np.histogram(arr, bins=10, range=(arr.min(), arr.max()), density=True)
+    density, bins = np.histogram(
+        arr, bins=10, range=(arr.min(), arr.max()), density=True
+    )
     assert type(density) is unyt_array
-    assert density.units == arr.units ** -1
+    assert density.units == arr.units**-1
     assert bins.units == arr.units
     # also check case with weights
     w = rng.uniform(size=1000) * g
-    wcounts, wbins = np.histogram(
-        arr, bins=10, range=(arr.min(), arr.max()), weights=w
-    )
+    wcounts, wbins = np.histogram(arr, bins=10, range=(arr.min(), arr.max()), weights=w)
     assert type(wcounts) is unyt_array
     assert wcounts.units == w.units
     assert wbins.units == arr.units
@@ -761,7 +761,9 @@ def test_histogramdd_with_weights_density():
     assert ywbins.units == y.units
     assert zwbins.units == z.units
     # also check case with weights and density
-    wdensity, (xwdbins, ywdbins, zwdbins) = np.histogramdd((x, y, z), weights=w, density=True)
+    wdensity, (xwdbins, ywdbins, zwdbins) = np.histogramdd(
+        (x, y, z), weights=w, density=True
+    )
     assert wdensity.ndim == 3
     assert type(wdensity) is unyt_array
     assert wdensity.units == w.units / (x.units * y.units * z.units)