code: def get_queryset(self):
          
          if self.queryset is None and not self.model:
              try:
                  ModelClass = apps.get_model(self.kwargs.get('app'), self.kwargs.get('model'))
                  return ModelClass._default_manager.all()
              except LookupError:
                  raise Http404()
          return super().get_queryset()
docs: Get queryset based on url params(<app>, <mode>) if model is not set on class