code: def followers_qs(self, actor, flag=''):
          
          check(actor)
          queryset = self.filter(
              content_type=ContentType.objects.get_for_model(actor),
              object_id=actor.pk
          ).select_related('user')
  
          if flag:
              queryset = queryset.filter(flag=flag)
          return queryset
docs: Returns a queryset of User objects who are following the given actor (eg my followers).