diff --git a/swiftgalaxy/halo_finders.py b/swiftgalaxy/halo_finders.py
index a522762..f848a78 100644
--- a/swiftgalaxy/halo_finders.py
+++ b/swiftgalaxy/halo_finders.py
@@ -102,7 +102,6 @@ def velocity_centre(self) -> cosmo_array:
 
 
 class Velociraptor(_HaloFinder):
-
     """
     Interface to velociraptor halo catalogues for use with :mod:`swiftgalaxy`.
 
@@ -371,7 +370,6 @@ def __repr__(self) -> str:
 
 
 class Caesar(_HaloFinder):
-
     """
     Interface to Caesar halo catalogues for use with :mod:`swiftgalaxy`.
 
diff --git a/swiftgalaxy/masks.py b/swiftgalaxy/masks.py
index f9eb1a2..c98288b 100644
--- a/swiftgalaxy/masks.py
+++ b/swiftgalaxy/masks.py
@@ -1,5 +1,4 @@
 class MaskCollection(object):
-
     """
     Barebones container for mask objects.
 
diff --git a/swiftgalaxy/reader.py b/swiftgalaxy/reader.py
index 98234d6..5c9099d 100644
--- a/swiftgalaxy/reader.py
+++ b/swiftgalaxy/reader.py
@@ -99,7 +99,6 @@ def _apply_4transform(
 
 
 class _CoordinateHelper(object):
-
     """
     Container class for coordinates.
 
@@ -135,7 +134,6 @@ def __repr__(self) -> str:
 
 
 class _SWIFTNamedColumnDatasetHelper(object):
-
     """
     A wrapper class to enable :class:`SWIFTGalaxy`
     functionality for a :class:`swiftsimio.reader.__SWIFTNamedColumnDataset`.
@@ -255,7 +253,6 @@ def _data_copy(
 
 
 class _SWIFTParticleDatasetHelper(object):
-
     """
     A wrapper class to enable :class:`SWIFTGalaxy`
     functionality for a :class:`swiftsimio.reader.__SWIFTParticleDataset`.
@@ -359,9 +356,9 @@ def __init__(
             TypeNamedColumnDatasetHelper = type(
                 nice_name, (_SWIFTNamedColumnDatasetHelper, object), dict()
             )
-            self._named_column_dataset_helpers[
-                named_columns_name
-            ] = TypeNamedColumnDatasetHelper(named_columns, self)
+            self._named_column_dataset_helpers[named_columns_name] = (
+                TypeNamedColumnDatasetHelper(named_columns, self)
+            )
         self._spherical_coordinates: Optional[dict] = None
         self._cylindrical_coordinates: Optional[dict] = None
         self._spherical_velocities: Optional[dict] = None
@@ -949,14 +946,14 @@ def _mask_derived_coordinates(self, mask: slice) -> None:
                 ][mask]
         if self._cylindrical_coordinates is not None:
             for coord in ("rho", "phi", "z"):
-                self._cylindrical_coordinates[
-                    f"_{coord}"
-                ] = self._cylindrical_coordinates[f"_{coord}"][mask]
+                self._cylindrical_coordinates[f"_{coord}"] = (
+                    self._cylindrical_coordinates[f"_{coord}"][mask]
+                )
         if self._cylindrical_velocities is not None:
             for coord in ("v_rho", "v_phi", "v_z"):
-                self._cylindrical_velocities[
-                    f"_{coord}"
-                ] = self._cylindrical_velocities[f"_{coord}"][mask]
+                self._cylindrical_velocities[f"_{coord}"] = (
+                    self._cylindrical_velocities[f"_{coord}"][mask]
+                )
         return
 
     def _void_derived_coordinates(self) -> None:
@@ -968,7 +965,6 @@ def _void_derived_coordinates(self) -> None:
 
 
 class SWIFTGalaxy(SWIFTDataset):
-
     """
     A representation of a simulated galaxy.
 
@@ -1303,27 +1299,27 @@ def _data_copy(self, mask_collection: Optional[MaskCollection] = None):
             if particle_dataset_helper._spherical_coordinates is not None:
                 new_particle_dataset_helper._spherical_coordinates = dict()
                 for c in ("_r", "_theta", "_phi"):
-                    new_particle_dataset_helper._spherical_coordinates[
-                        c
-                    ] = particle_dataset_helper._spherical_coordinates[c][mask]
+                    new_particle_dataset_helper._spherical_coordinates[c] = (
+                        particle_dataset_helper._spherical_coordinates[c][mask]
+                    )
             if particle_dataset_helper._spherical_velocities is not None:
                 new_particle_dataset_helper._spherical_velocities = dict()
                 for c in ("_v_r", "_v_t", "_v_p"):
-                    new_particle_dataset_helper._spherical_velocities[
-                        c
-                    ] = particle_dataset_helper._spherical_velocities[c][mask]
+                    new_particle_dataset_helper._spherical_velocities[c] = (
+                        particle_dataset_helper._spherical_velocities[c][mask]
+                    )
             if particle_dataset_helper._cylindrical_coordinates is not None:
                 new_particle_dataset_helper._cylindrical_coordinates = dict()
                 for c in ("_rho", "_phi", "_z"):
-                    new_particle_dataset_helper._cylindrical_coordinates[
-                        c
-                    ] = particle_dataset_helper._cylindrical_coordinates[c][mask]
+                    new_particle_dataset_helper._cylindrical_coordinates[c] = (
+                        particle_dataset_helper._cylindrical_coordinates[c][mask]
+                    )
             if particle_dataset_helper._cylindrical_velocities is not None:
                 new_particle_dataset_helper._cylindrical_velocities = dict()
                 for c in ("_v_rho", "_v_phi", "_v_z"):
-                    new_particle_dataset_helper._cylindrical_velocities[
-                        c
-                    ] = particle_dataset_helper._cylindrical_velocities[c][mask]
+                    new_particle_dataset_helper._cylindrical_velocities[c] = (
+                        particle_dataset_helper._cylindrical_velocities[c][mask]
+                    )
         return SG
 
     def __getattribute__(self, attr: str) -> Any:
diff --git a/tests/toysnap.py b/tests/toysnap.py
index 715625b..398173c 100644
--- a/tests/toysnap.py
+++ b/tests/toysnap.py
@@ -838,9 +838,9 @@ def create_toycaesar(filename=toycaesar_filename):
         # f["/simulation_attributes"].attrs["effective_resolution"] = ...
         # f["/simulation_attributes"].attrs["fullpath"] = ...
         f["/simulation_attributes"].attrs["hubble_constant"] = 0.7
-        f["/simulation_attributes"].attrs[
-            "mean_interparticle_separation"
-        ] = boxsize.to_value(u.kpc) / n_dm ** (1 / 3)
+        f["/simulation_attributes"].attrs["mean_interparticle_separation"] = (
+            boxsize.to_value(u.kpc) / n_dm ** (1 / 3)
+        )
         f["/simulation_attributes"].attrs["nbh"] = n_bh
         f["/simulation_attributes"].attrs["ndm"] = n_dm_all
         f["/simulation_attributes"].attrs["ndust"] = 0