Refactor getting of user model in auth backend.

test_oauth/backend.py

@@ -5,15 +5,12 @@ from django.conf import settings
 from django.db import transaction
 
 
-UserModel = get_user_model()
-
-
 class TESTOAuth2Backend(ModelBackend):
     def authenticate(self, id=None, username=None, **profile):
         if id is None or username is None:
             return None
 
-        user, _ = UserModel.objects.get_or_create(
+        user, _ = get_user_model().objects.get_or_create(
             pk=id,
             username=username
         )
@@ -24,6 +21,8 @@ class TESTOAuth2Backend(ModelBackend):
         return user
 
     def get_user(self, user_id):
+        UserModel = get_user_model()
+
         try:
             return UserModel.objects.get(pk=user_id)
         except UserModel.DoesNotExist: