code: def get_queryset(self):
          
          qs = VersionedQuerySet(self.model, using=self._db)
          if hasattr(self, 'instance') and hasattr(self.instance, '_querytime'):
              qs.querytime = self.instance._querytime
          return qs
docs: Returns a VersionedQuerySet capable of handling version time
          restrictions.
  
          :return: VersionedQuerySet