def get_face_fun_on(self):
        """
        determine extend fmt
        """
        command = const.CMD_OPTIONS_RRQ
        command_string = b'FaceFunOn\x00'
        response_size = 1024

        cmd_response = self.__send_command(command, command_string, response_size)
        if cmd_response.get('status'):
            response = (self.__data.split(b'=', 1)[-1].split(b'\x00')[0])
            return safe_cast(response, int ,0) if response else 0
        else:
            self._clear_error(command_string)
            return None
determine extend fmt