class_docstr: Filesystem that uses local file operations.
code: def walk(
      top: PathType,
      topdown: bool = True,
      onerror: Optional[Callable[..., None]] = None,
  ) -> Iterable[Tuple[PathType, List[PathType], List[PathType]]]:
      try:
          yield from os.walk(top, topdown=topdown, onerror=onerror)
      except FileNotFoundError as e:
          raise filesystem.NotFoundError() from e
  
imports: import glob
  import os
  import shutil
  from typing import Any, Callable, Iterable, List, Optional, Tuple
  from tfx.dsl.io import filesystem
  from tfx.dsl.io import filesystem_registry
  from tfx.dsl.io.filesystem import PathType
label_desc: Use image node_id 13 for calling the LocalFilesystem obj's underlying member method code with example usage: obj.walk(top, topdown, onerror) without return types