fix:username-disambiguation

kolibri/core/auth/backends.py

@@ -34,6 +34,7 @@ def authenticate(self, request, username=None, password=None, **kwargs):
         # If case-sensitive login fails, attempt case-insensitive login
         user = self.authenticate_case_insensitive(username, password, facility)
         return user
+
     def _authenticate_users(self, users, password, facility):
         if facility:
             users = users.filter(facility=facility)
@@ -50,13 +51,15 @@ def _authenticate_users(self, users, password, facility):
             ):
                 return user
         return None
+
     def authenticate_case_sensitive(self, username, password, facility):
         users = FacilityUser.objects.filter(username=username)
         return self._authenticate_users(users, password, facility)
 
     def authenticate_case_insensitive(self, username, password, facility):
         users = FacilityUser.objects.filter(username__iexact=username)
         return self._authenticate_users(users, password, facility)
+
     def get_user(self, user_id):
         """
         Gets a user. Auth backends are required to implement this.