def _is_json_serialized_jws(self, json_jws):
        """
        Check if we've got a JSON serialized signed JWT.

        :param json_jws: The message
        :return: True/False
        """
        json_ser_keys = {"payload", "signatures"}
        flattened_json_ser_keys = {"payload", "signature"}
        if not json_ser_keys.issubset(
                json_jws.keys()) and not flattened_json_ser_keys.issubset(
                json_jws.keys()):
            return False
        return True
Check if we've got a JSON serialized signed JWT.

        :param json_jws: The message
        :return: True/False