code: def get_local_dir():
      if _HUB_ROOT is not None:
          return _HUB_ROOT
      cache_root = os.path.expanduser(
          os.getenv(ENV_TOWHEE_HOME, DEFAULT_CACHE_DIR)
      )
      return cache_root
  
file_path: towhee/towhee/hub/cache_manager.py
imports: import os
  from pathlib import Path
  import threading
  from .downloader import download_operator, download_pipeline, repo_tag_path
label_desc: Use image node_id 2 for calling a global function with example usage: get_local_dir() and returns: cache_root, _HUB_ROOT