code: def _btime(self):
      if not self.tmp_dir:
          return None
  
      # Not all python versions/filesystems/platforms provide creation
      # time (st_birthtime, stx_btime, etc), so we use our own dummy
      # file and its mtime instead.
      path = os.path.join(self.tmp_dir, "btime")
  
      try:
          with open(path, "x"):
              pass
      except FileNotFoundError:
          return None
      except FileExistsError:
          pass
  
      return os.path.getmtime(path)
  
imports: import os
  from collections import defaultdict
  from contextlib import contextmanager
  from functools import wraps
  from typing import TYPE_CHECKING, Callable, ContextManager, Iterable, Optional, Tuple, Union
  from dvc.exceptions import DvcException, NotDvcRepoError, OutputNotFoundError, RevCollectionError
  from dvc.ignore import DvcIgnoreFilter
  from dvc.log import logger
  from dvc.utils.objects import cached_property
label_desc: Use image node_id 33 for calling the Repo obj's underlying member method code with example usage: obj._btime() and returns: os, None, None