code: def iter_run_dirs(root=None):
      return _iter_dirs(root or runs_dir())
  
imports: import errno
  import functools
  import logging
  import os
  import shutil
  import tempfile
  from guild import config
  from guild import run
  from guild import util
label_desc: Use image node_id 18 for calling a global function with example usage: iter_run_dirs(root) and returns: _iter_dirs