docstr: Keep a datafs instance of each repo.
code: def _datafss(self):
      """Keep a datafs instance of each repo."""
  
      datafss = {}
  
      if hasattr(self.repo, "dvc_dir"):
          key = self._get_key(self.repo.root_dir)
          datafss[key] = DataFileSystem(
              index=self.repo.index.data["repo"]
          )
  
      return datafss
  
imports: import errno
  import functools
  import ntpath
  import os
  import posixpath
  import threading
  from collections import deque
  from contextlib import ExitStack, suppress
  from typing import TYPE_CHECKING, Any, Callable, Dict, Optional, Tuple, Type, Union
  from fsspec.spec import AbstractFileSystem
  from funcy import wrap_with
  from dvc.log import logger
  from dvc_objects.fs.base import FileSystem
  from .data import DataFileSystem
label_desc: Use image node_id 16 for calling the _DVCFileSystem obj's underlying member method code with example usage: obj._datafss() and returns: datafss