class_docstr: DatasetBuilder for RLU.
code: def get_episode_id(self, episode):
      # The key of the episode is converted to string because int64 is not
      # supported as key.
      return str(episode["episode_id"])
  
imports: from __future__ import annotations
  import os
  from typing import Any, Dict, Generator, List, Tuple
  import numpy
  from tensorflow_datasets.core.utils.lazy_imports_utils import tensorflow
  import tensorflow_datasets.public_api
label_desc: Use image node_id 7 for calling the RLUBuilder obj's underlying member method code with example usage: obj.get_episode_id(episode) and returns: str