docs: def create_relationships(cls, id, related_collection_name, request_json):
          r"""
          Used to create relationship(s) between the id node and the nodes identified in the included resource \
          identifier objects.
  
          :param id: The 'id' field of the node on the left side of the relationship in the database.  The id field must \
          be set in the model -- it is not the same as the node id
          :param related_collection_name: The name of the relationship
          :param request_json: request_json: a dictionary formatted according to the specification at \
          http://jsonapi.org/format/#crud-updating-relationships
          :return: A response according to the same specification
          """
          try:
              this_resource = cls.nodes.get(id=id, active=True)
              related_collection = getattr(this_resource, related_collection_name)
              if type(related_collection) in (One, ZeroOrOne):  # Cardinality <= 1 so update_relationship should be used
                  r = application_codes.error_response([application_codes.FORBIDDEN_VIOLATION])
              else:
                  data = request_json['data']
                  for rsrc_identifier in data:
                      the_new_node = cls.get_class_from_type(rsrc_identifier['type']).nodes.get(id=rsrc_identifier['id'])
                      rel_attrs = rsrc_identifier.get('meta')
                      if not rel_attrs or isinstance(rel_attrs, dict):
                          related_collection.connect(the_new_node, rel_attrs)
                      else:
                          raise WrongTypeError
                  #r = this_resource.relationship_collection_response(related_collection_name)
                  r = make_response('')
                  r.status_code = http_error_codes.NO_CONTENT
                  r.headers['Content-Type'] = CONTENT_TYPE
  
          except DoesNotExist:
              r = application_codes.error_response([application_codes.RESOURCE_NOT_FOUND])
          except (KeyError, TypeError, WrongTypeError):
              r = application_codes.error_response([application_codes.BAD_FORMAT_VIOLATION])
          except AttemptedCardinalityViolation:
              r = application_codes.error_response([application_codes.ATTEMPTED_CARDINALITY_VIOLATION])
          except MultipleNodesReturned:
              r = application_codes.error_response([application_codes.MULTIPLE_NODES_WITH_ID_VIOLATION])
          return r