code: def bulk_add_entities(self, entities_and_kinds):
          
          memberships = [EntityGroupMembership(
              entity_group=self,
              entity=entity,
              sub_entity_kind=sub_entity_kind,
          ) for entity, sub_entity_kind in entities_and_kinds]
          created = EntityGroupMembership.objects.bulk_create(memberships)
          return created
docs: Add many entities and sub-entity groups to this EntityGroup.
  
          :type entities_and_kinds: List of (Entity, EntityKind) pairs.
          :param entities_and_kinds: A list of entity, entity-kind pairs
              to add to the group. In the pairs the entity-kind can be
              ``None``, to add a single entity, or some entity kind to
              add all sub-entities of that kind.