code: def stop(self):
          
  
          yield from self._stop_ubridge()
          if self._nvram_watcher:
              self._nvram_watcher.close()
              self._nvram_watcher = None
  
          if self._telnet_server:
              self._telnet_server.close()
              self._telnet_server = None
  
          if self.is_running():
              self._terminate_process_iou()
              if self._iou_process.returncode is None:
                  try:
                      yield from gns3server.utils.asyncio.wait_for_process_termination(self._iou_process, timeout=3)
                  except asyncio.TimeoutError:
                      if self._iou_process.returncode is None:
                          log.warning("IOU process {} is still running... killing it".format(self._iou_process.pid))
                          try:
                              self._iou_process.kill()
                          except ProcessLookupError:
                              pass
              self._iou_process = None
  
          self._started = False
          self.save_configs()
docs: Stops the IOU process.