str: The Sonos descriptor to use for this service.

        The Sonos descriptor is used as the content of the <desc> tag in
        DIDL metadata, to indicate the relevant music service id and username.

def desc(self):
        """str: The Sonos descriptor to use for this service.

        The Sonos descriptor is used as the content of the <desc> tag in
        DIDL metadata, to indicate the relevant music service id and username.
        """
        desc = "SA_RINCON{}_{}".format(
            self.account.service_type, self.account.username
        )
        return desc