code: def _send_heartbeat(self):
      if self._remote_client():
          try:
              response = self._remote_client().client_heartbeat()
              if (
                  response.status
                  == rpc_messages.HeartbeatResponse.Status.OK
              ):
                  self._heartbeat_responses["success"] += 1
              else:
                  self._heartbeat_responses["fail"] += 1
          except Exception:
              # at the moment we don't care about failures for heartbeats
              self._heartbeat_responses["fail"] += 1
  
imports: import datetime
  import logging
  import time
  import weakref
  from collections import Counter
  from threading import Thread
  from typing import Union
  import aim.ext.transport.proto.remote_router_pb2
label_desc: Use image node_id 4 for calling the RPCHeartbeatSender obj's underlying member method code with example usage: obj._send_heartbeat() without return types