code: def _notify_media_transport_available(self, path, transport):
          
          self.sink = BTAudioSink(dev_path=path)
          self.state = self.sink.State
          self.sink.add_signal_receiver(self._property_change_event_handler,
                                        BTAudioSource.SIGNAL_PROPERTY_CHANGED,  # noqa
                                        transport)
docs: Called by the endpoint when a new media transport is
          available