code: def test_get_listening_tcp_ports():
      assert not list_current_ports()
      with IPCServer(lambda _: None) as server:
          assert list_current_ports() == [server.port]
      assert not list_current_ports()
  
imports: import contextlib
  import pickle
  import random
  import socket
  import sys
  import threading
  import time
  import psutil
  import pytest
  import retrying
  from fiftyone.service.ipc import IPCServer, send_request
  from fiftyone.service.util import find_processes_by_args, get_listening_tcp_ports, normalize_wrapper_process, send_ipc_message
label_desc: Use image node_id 13 for calling a global function with example usage: test_get_listening_tcp_ports() without return types