code: def __init__(self, dataset_key_dir: str):
      self._cache_metadata_path = os.path.join(
          dataset_key_dir, f"{_METADATA_FILE_NAME}-*-of-*"
      )
  
imports: import os
  import pickle
  import re
  import sys
  from typing import Iterable, Mapping, List, Optional, Union, Tuple
  import apache_beam
  import tensorflow
  from tfx_bsl.types import tfx_namedtuple
label_desc: Use image node_id 1 to create a new _ReadMetadata object from inherited base classes: beam with example: obj = _ReadMetadata(dataset_key_dir)