code: def _make_flattened_dataset_key() -> DatasetKey:
      return DatasetKey(
          DatasetKey._FLATTENED_DATASET_KEY, is_cached=False
      )
  
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 2 for calling a global function with example usage: _make_flattened_dataset_key() and returns: DatasetKey