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)