code: def disconnect():
      """Disconnect the global client from the master node."""
      global GLOBAL_CLIENT
      if GLOBAL_CLIENT is not None:
          GLOBAL_CLIENT.destroy()
          GLOBAL_CLIENT = None
          logger.info("The client is disconneced to the master node.")
      else:
          logger.info(
              "No client to be released. Please make sure that you have called `parl.connect`"
          )
  
imports: import cloudpickle
  import datetime
  import os
  import socket
  import sys
  import threading
  import zmq
  import parl
  import time
  import glob
  import multiprocessing
  from parl.utils import to_str, to_byte, get_ip_address, logger, isnotebook
  from parl.remote.utils import get_subfiles_recursively
  from parl.remote import remote_constants
  from parl.remote.grpc_heartbeat import HeartbeatServerThread, HeartbeatServerProcess
  from parl.remote.utils import get_version
label_desc: Use image node_id 3 for calling a global function with example usage: disconnect() without return types