code: def _handle(self, req, client_address):
      if isinstance(req, HostsUpdatedRequest):
          self._manager.handle_hosts_updated(req.timestamp, req.res)
          return network.AckResponse()
  
      return super(WorkerNotificationService, self)._handle(
          req, client_address
      )
  
imports: import os
  import threading
  from enum import IntFlag
  from horovod.runner.common.util import network, secret
  from horovod.runner.elastic.rendezvous import PUT_WORKER_ADDRESSES
  from horovod.runner.http.http_client import put_data_into_kvstore
label_desc: Use image node_id 2 for calling the WorkerNotificationService obj's underlying member method code with example usage: obj._handle(req, client_address) and returns: super, network