docstr: Tests that rank_zero_read_and_broadcast decorator works as expected
docstr_tok: ["Tests","that","rank_zero_read_and_broadcast","decorator","works","as","expected"]
code: def _test_rank_zero_read_and_broadcast() -> None:
      """
      Tests that rank_zero_read_and_broadcast decorator works as expected
      """
  
      @rank_zero_read_and_broadcast
      def _test_method_for_rank_zero() -> str:
          assert get_global_rank() == 0
          return "foo"
  
      init_from_env()
      val_from_test_method = _test_method_for_rank_zero()
      tc = unittest.TestCase()
      tc.assertEqual(val_from_test_method, "foo")
  
imports: import os
  import shutil
  import tempfile
  import unittest
  import torch
  import torch.distributed
  from torch import nn
  from torch.distributed import launcher
  from torchsnapshot import Snapshot
  from torchsnapshot.snapshot import SNAPSHOT_METADATA_FNAME
  from torchtnt.framework._test_utils import DummyTrainUnit, get_dummy_train_state
  from torchtnt.framework.callbacks._checkpoint_utils import _delete_checkpoint, _metadata_exists, _prepare_app_state_for_checkpoint, _retrieve_checkpoint_dirpaths, get_checkpoint_dirpaths, get_latest_checkpoint_path, rank_zero_read_and_broadcast
  from torchtnt.utils.distributed import get_global_rank, PGWrapper
  from torchtnt.utils.env import init_from_env
  from torchtnt.utils.fsspec import get_filesystem
  from torchtnt.utils.test_utils import get_pet_launch_config, spawn_multi_process
label_desc: Use image node_id 13 for calling the CheckpointUtilsTest obj's underlying member method code with example usage: obj._test_rank_zero_read_and_broadcast() and returns: str