diff --git a/categories/__init__.py b/categories/__init__.py
index 1eb3387..509879e 100644
--- a/categories/__init__.py
+++ b/categories/__init__.py
@@ -2,5 +2,4 @@
 __version__ = "1.8.0"
 
 
-
 default_app_config = "categories.apps.CategoriesConfig"
diff --git a/categories/editor/tree_editor.py b/categories/editor/tree_editor.py
index 45c70d1..2d64b51 100644
--- a/categories/editor/tree_editor.py
+++ b/categories/editor/tree_editor.py
@@ -232,11 +232,14 @@ class TreeEditor(admin.ModelAdmin):
                         name = force_text(opts.verbose_name)
                     else:
                         name = force_text(opts.verbose_name_plural)
-                    msg = ungettext(
-                        "%(count)s %(name)s was changed successfully.",
-                        "%(count)s %(name)s were changed successfully.",
-                        changecount,
-                    ) % {"count": changecount, "name": name, "obj": force_text(obj)}
+                    msg = (
+                        ungettext(
+                            "%(count)s %(name)s was changed successfully.",
+                            "%(count)s %(name)s were changed successfully.",
+                            changecount,
+                        )
+                        % {"count": changecount, "name": name, "obj": force_text(obj)}
+                    )
                     self.message_user(request, msg)
 
                 return HttpResponseRedirect(request.get_full_path())
diff --git a/categories/migration.py b/categories/migration.py
index 77358a5..ac4f36c 100644
--- a/categories/migration.py
+++ b/categories/migration.py
@@ -1,5 +1,3 @@
-
-
 from django.apps import apps
 from django.db import connection, transaction
 from django.db.utils import ProgrammingError
diff --git a/categories/migrations/0001_initial.py b/categories/migrations/0001_initial.py
index 883fd62..23afb6a 100644
--- a/categories/migrations/0001_initial.py
+++ b/categories/migrations/0001_initial.py
@@ -1,5 +1,3 @@
-
-
 import django.core.files.storage
 import mptt.fields
 from django.db import migrations, models
diff --git a/categories/tests/test_admin.py b/categories/tests/test_admin.py
index ce1c7a3..4875889 100644
--- a/categories/tests/test_admin.py
+++ b/categories/tests/test_admin.py
@@ -1,4 +1,3 @@
-
 from django.contrib.auth.models import User
 from django.test import Client, TestCase
 from django.urls import reverse