class_docstr: DatasetBuilder for robomimic_ph dataset.
code: def _get_metadata(self) -> Dict[Any, Any]:
      if self.builder_config.task != utils.Task.TOOL_HANG:
          episode_metadata = {
              "20_percent": np.bool_,
              "20_percent_train": np.bool_,
              "20_percent_valid": np.bool_,
              "50_percent": np.bool_,
              "50_percent_train": np.bool_,
              "50_percent_valid": np.bool_,
              "train": np.bool_,
              "valid": np.bool_,
          }
      else:
          episode_metadata = {
              "train": np.bool_,
              "valid": np.bool_,
          }
      return episode_metadata
  
imports: from __future__ import annotations
  from typing import Any, Dict
  import numpy
  import tensorflow_datasets.public_api
  from tensorflow_datasets.robomimic import dataset_utils
label_desc: Use image node_id 1 for calling the Builder obj's underlying member method code with example usage: obj._get_metadata() and returns: episode_metadata