code: def world_size():
      remove_env_var = False
  
      if "WORLD_SIZE" not in os.environ:
          os.environ["WORLD_SIZE"] = "1"
          remove_env_var = True
  
      yield int(os.environ["WORLD_SIZE"])
  
      if remove_env_var:
          del os.environ["WORLD_SIZE"]
  
imports: import functools
  import os
  import shutil
  import sys
  import tempfile
  import time
  from pathlib import Path
  import pytest
  import torch
  import torch.distributed
  import ignite.distributed
label_desc: Use image node_id 6 for calling a global function with example usage: world_size() without return types