code: def _runs_under_parent_f(root):
      runs_parent = os.getenv("GUILD_RUNS_PARENT")
      if not runs_parent:
          return None
      log.debug("limitting to runs under parent %s", runs_parent)
      return lambda: _runs_for_parent(runs_parent, root)
  
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 12 for calling a global function with example usage: _runs_under_parent_f(root) and returns: function, None