stops the current trajectory (turns off the motors)

        :param group_mask: mask for which CFs this should apply to
        :return:

def stop(self, group_mask=ALL_GROUPS):
        """
        stops the current trajectory (turns off the motors)

        :param group_mask: mask for which CFs this should apply to
        :return:
        """
        self._send_packet(struct.pack('<BB',
                                      self.COMMAND_STOP,
                                      group_mask))