bool: Is the playbar speaker input from TV?

def is_playing_tv(self):
        """bool: Is the playbar speaker input from TV?"""
        response = self.avTransport.GetPositionInfo([
            ('InstanceID', 0),
            ('Channel', 'Master')
        ])
        track_uri = response['TrackURI']
        return re.match(r'^x-sonos-htastream:', track_uri) is not None