code: def disconnect_channel(self, destination_id):
          
          if destination_id in self._open_channels:
              try:
                  self.send_message(
                      destination_id, NS_CONNECTION,
                      {MESSAGE_TYPE: TYPE_CLOSE, 'origin': {}},
                      no_add_request_id=True, force=True)
              except NotConnected:
                  pass
              except Exception:  # pylint: disable=broad-except
                  self.logger.exception("[%s:%s] Exception",
                                        self.fn or self.host, self.port)
  
              self._open_channels.remove(destination_id)
  
              self.handle_channel_disconnected()
docs: Disconnect a channel with destination_id.