docs: def get_op_restrictions_by_content_operation(self, content_id, operation_key, expand=None, start=None, limit=None,
                                                   callback=None):
          """
          Returns info about all restrictions of given operation.
          :param content_id (string): The content ID to query on.
          :param operation_key (string): The operation key to query on.
          :param expand (string): OPTIONAL: A comma separated list of properties to expand on the content properties.
                                  Default: Again, this is unclear/inconsistent when reading documentation. The REST
                                      documentation claims that both are default:
                                          "group"
                                          "restrictions.user,restrictions.group"
          :param start (int): Pagination start count.
          :param limit (int): Pagination return count limit.
          :param callback: OPTIONAL: The callback to execute on the resulting data, before the method returns.
                           Default: None (no callback, raw data returned).
          :return: The JSON data returned from the content/{id}/restriction/byOperation/{operationKey} endpoint,
                   or the results of the callback. Will raise requests.HTTPError on bad input, potentially.
          """
          params = {}
          if expand:
              params["expand"] = expand
          if start is not None:
              params["start"] = int(start)
          if limit is not None:
              params["limit"] = int(limit)
          return self._service_get_request("rest/api/content/{id}/restriction/byOperation/{opkey}"
                                           "".format(id=content_id, opkey=operation_key),
                                           params=params, callback=callback)