Parse a mysensors command string.

        Return a MQTT topic, payload and qos-level as a tuple.

def _parse_message_to_mqtt(self, data):
        """Parse a mysensors command string.

        Return a MQTT topic, payload and qos-level as a tuple.
        """
        msg = Message(data, self)
        payload = str(msg.payload)
        msg.payload = ''
        # prefix/node/child/type/ack/subtype : payload
        return ('{}/{}'.format(self._out_prefix, msg.encode('/'))[:-2],
                payload, msg.ack)