class_docstr: Dataset with additional indexing information.
code: def _normalize_example(
      self,
      data: JsonDict,
      ex_id: ExampleId,
      meta: lit_types.InputMetadata,
  ):
      return types.MappingProxyType(dict(data, _id=ex_id, _meta=meta))
  
imports: from collections.abc import Callable, Mapping, Sequence
  import hashlib
  import glob
  import inspect
  import os
  import random
  import types
  from typing import Optional, Union, cast
  from absl import logging
  from lit_nlp.api import types
  from lit_nlp.lib import serialize
  from lit_nlp.lib import utils
label_desc: Use image node_id 1 for calling the IndexedDataset obj's underlying member method code with example usage: obj._normalize_example(data, ex_id, meta) and returns: types