code: def test_matches_machine_hostname_returns_true_if_hostname_is_loopback(
      self,
  ) -> None:
      hosts = [
          "localhost",
          "127.0.0.1",
          "::1",
          "0000:0000:0000:0000:0000:0000:0000:0001",
      ]
  
      for host in hosts:
          with self.subTest(host=host):
              self.assertTrue(_matches_machine_hostname(host))
  
imports: import threading
  import time
  import socket
  from datetime import timedelta
  from typing import List
  from unittest import TestCase
  from unittest.mock import patch
  from torch.distributed.elastic.rendezvous.utils import _PeriodicTimer, _delay, _matches_machine_hostname, _parse_rendezvous_config, _try_parse_port, parse_rendezvous_endpoint
label_desc: Use image node_id 13 for calling the UtilsTest obj's underlying member method code with example usage: obj.test_matches_machine_hostname_returns_true_if_hostname_is_loopback() without return types