code: def test_get_tcp_init_method(self) -> None:
      world_size = 10
      rank = 2
      my_hostname = "my_hostname"
      my_port = 1234
      init_method = get_tcp_init_method(
          world_size=world_size,
          rank=rank,
          hostname=my_hostname,
          port=my_port,
      )
      url = urlparse(init_method)
      self.assertEqual(url.scheme, "tcp")
      self.assertEqual(url.hostname, my_hostname)
      self.assertEqual(url.port, my_port)
      self.assertEqual(url.path, "")
      url_qs = parse_qs(url.query)
      self.assertIn("world_size", url_qs)
      self.assertEqual(url_qs["world_size"], [str(world_size)])
      self.assertIn("rank", url_qs)
      self.assertEqual(url_qs["rank"], [str(rank)])
  
      world_size = 2
      rank = 1
      my_hostname = "my_hostname"
      # get free port
      init_method = get_tcp_init_method(
          world_size=world_size,
          rank=rank,
          hostname=my_hostname,
          port=None,
      )
      url = urlparse(init_method)
      self.assertEqual(url.scheme, "tcp")
      self.assertEqual(url.hostname, my_hostname)
      self.assertIsNotNone(url.port)
      self.assertTrue(none_throws(url.port) > 0)
      self.assertEqual(url.path, "")
      url_qs = parse_qs(url.query)
      self.assertIn("world_size", url_qs)
      self.assertEqual(url_qs["world_size"], [str(world_size)])
      self.assertIn("rank", url_qs)
      self.assertEqual(url_qs["rank"], [str(rank)])
  
      world_size = 12
      rank = 7
      my_port = 4321
      # get localhost
      init_method = get_tcp_init_method(
          world_size=world_size, rank=rank, hostname=None, port=my_port
      )
      url = urlparse(init_method)
      self.assertEqual(url.scheme, "tcp")
      self.assertIsNotNone(url.hostname)
      self.assertTrue(none_throws(url.hostname).startswith("localhost"))
      self.assertEqual(url.port, my_port)
      self.assertEqual(url.path, "")
      url_qs = parse_qs(url.query)
      self.assertIn("world_size", url_qs)
      self.assertEqual(url_qs["world_size"], [str(world_size)])
      self.assertIn("rank", url_qs)
      self.assertEqual(url_qs["rank"], [str(rank)])
  
      world_size = 128
      rank = 43
      # get localhost and free port
      init_method = get_tcp_init_method(
          world_size=world_size, rank=rank
      )
      url = urlparse(init_method)
      self.assertEqual(url.scheme, "tcp")
      self.assertIsNotNone(url.hostname)
      self.assertTrue(none_throws(url.hostname).startswith("localhost"))
      self.assertIsNotNone(url.port)
      self.assertTrue(none_throws(url.port) > 0)
      self.assertEqual(url.path, "")
      url_qs = parse_qs(url.query)
      self.assertIn("world_size", url_qs)
      self.assertEqual(url_qs["world_size"], [str(world_size)])
      self.assertIn("rank", url_qs)
      self.assertEqual(url_qs["rank"], [str(rank)])
  
imports: import os
  import unittest
  from typing import Literal, Optional, Union
  from unittest.mock import MagicMock, patch
  from urllib.parse import parse_qs, urlparse
  import torch
  import torch.distributed
  import torch.distributed.launcher
  from pyre_extensions import none_throws
  from torchtnt.utils.distributed import _validate_global_rank_world_size, all_gather_tensors, destroy_process_group, get_file_init_method, get_global_rank, get_local_rank, get_local_world_size, get_process_group_backend_from_device, get_tcp_init_method, get_world_size, PGWrapper, rank_zero_fn, revert_sync_batchnorm, sync_bool
  from torchtnt.utils.test_utils import get_pet_launch_config
label_desc: Use image node_id 32 for calling the DistributedTest obj's underlying member method code with example usage: obj.test_get_tcp_init_method() without return types