docs: def _publish_status(self, port):
          '''
          Publish status for specified port.
  
          Parameters
          ----------
          port : str
              Device name/port.
          '''
          if port not in self.open_devices:
              status = {}
          else:
              device = self.open_devices[port].serial
              properties = ('port', 'baudrate', 'bytesize', 'parity', 'stopbits',
                            'timeout', 'xonxoff', 'rtscts', 'dsrdtr')
              status = {k: getattr(device, k) for k in properties}
          status_json = json.dumps(status)
          self.mqtt_client.publish(topic='serial_device/%s/status' % port,
                                   payload=status_json, retain=True)