diff --git a/src/whitenoise/middleware.py b/src/whitenoise/middleware.py
index 2deba90d..9f8d8d6e 100644
--- a/src/whitenoise/middleware.py
+++ b/src/whitenoise/middleware.py
@@ -71,15 +71,18 @@ def process_request(self, request):
 
         if settings.DEBUG and request.path.startswith(settings.STATIC_URL):
             from django.contrib.staticfiles.finders import get_finders
+
             finders = get_finders()
             app_dirs = []
             for finder in finders:
                 for storage in finder.storages.values():
                     app_dirs.append(storage.location)
             app_dirs = "\n    ".join(sorted(app_dirs))
-            raise MissingFileError(f"""{request.path} not found. Searched these paths:
+            raise MissingFileError(
+                f"""{request.path} not found. Searched these paths:
 
-    {app_dirs}""")
+    {app_dirs}"""
+            )
 
     @staticmethod
     def serve(static_file, request):
diff --git a/tests/django_urls.py b/tests/django_urls.py
index f4ce2222..157b9b17 100644
--- a/tests/django_urls.py
+++ b/tests/django_urls.py
@@ -7,6 +7,4 @@ def avoid_django_default_welcome_page():
     pass
 
 
-urlpatterns = [
-    path('', avoid_django_default_welcome_page)
-]
+urlpatterns = [path("", avoid_django_default_welcome_page)]
diff --git a/tests/test_django_whitenoise.py b/tests/test_django_whitenoise.py
index cb80d177..1285e22b 100644
--- a/tests/test_django_whitenoise.py
+++ b/tests/test_django_whitenoise.py
@@ -215,15 +215,15 @@ def test_relative_static_url(server, static_files, _collect_static):
 
 
 def test_404_in_prod(server):
-    response = server.get(settings.STATIC_URL + 'garbage')
+    response = server.get(settings.STATIC_URL + "garbage")
     assert response.status_code == 404
 
 
 @override_settings(DEBUG=True)
 def test_error_message(server):
-    response = server.get(settings.STATIC_URL + 'garbage')
+    response = server.get(settings.STATIC_URL + "garbage")
     print(response.content.decode())
-    app_dirs = Path(__file__).parent / 'test_files' / 'static'
+    app_dirs = Path(__file__).parent / "test_files" / "static"
 
     expected = f"""{settings.STATIC_URL + 'garbage'} not found. Searched these paths: