code: def clean_env():
      for k in ["RANK", "LOCAL_RANK", "WORLD_SIZE"]:
          if k in os.environ:
              del os.environ[k]
  
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 7 for calling a global function with example usage: clean_env() without return types