diff --git a/constance/management/commands/constance.py b/constance/management/commands/constance.py
index e226026..b6b4b2c 100644
--- a/constance/management/commands/constance.py
+++ b/constance/management/commands/constance.py
@@ -70,8 +70,8 @@ class Command(BaseCommand):
             for k, v in get_values().items():
                 self.stdout.write(f"{k}\t{v}", ending="\n")
         elif command == self.REMOVE_STALE_KEYS:
-            prefix = getattr(settings, 'CONSTANCE_DATABASE_PREFIX', '')
-            actual_keys = [f'{prefix}{key}' for key in settings.CONSTANCE_CONFIG]
+            prefix = getattr(settings, "CONSTANCE_DATABASE_PREFIX", "")
+            actual_keys = [f"{prefix}{key}" for key in settings.CONSTANCE_CONFIG]
             stale_records = Constance.objects.exclude(key__in=actual_keys)
             if stale_records:
                 self.stdout.write("The following record will be deleted:", ending="\n")
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 1cc8c0a..db022f2 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -120,13 +120,13 @@ class CliTestCase(TransactionTestCase):
         self.assertEqual(Constance.objects.count(), initial_count, msg=self.out)
 
     @override_settings(
-        CONSTANCE_DATABASE_PREFIX='constance:',
+        CONSTANCE_DATABASE_PREFIX="constance:",
     )
     def test_delete_stale_records_respects_prefix(self):
         self._populate_database_with_default_values()
         initial_count = Constance.objects.count()
 
-        call_command('constance', 'remove_stale_keys', stdout=self.out)
+        call_command("constance", "remove_stale_keys", stdout=self.out)
 
         self.assertEqual(Constance.objects.count(), initial_count, msg=self.out)
 
@@ -136,4 +136,4 @@ class CliTestCase(TransactionTestCase):
         in settings since that's not done automatically at startup
         """
         for key, (value, *_) in settings.CONSTANCE_CONFIG.items():
-            Constance.objects.create(key=f'{getattr(settings, "CONSTANCE_DATABASE_PREFIX", "")}{key}', value=value)
+            Constance.objects.create(key=f"{getattr(settings, 'CONSTANCE_DATABASE_PREFIX', '')}{key}", value=value)