sort imports using isort. tested.

core/middleware.py

@@ -1,6 +1,7 @@
-from django.conf import settings
 from django import http
-from django.urls import reverse, resolve,Resolver404
+from django.conf import settings
+from django.urls import Resolver404, resolve, reverse
+
 """Non-standard django middleware is loaded from this file.
 
 """