See base class for details.

def load_metadata(self, data_dir, feature_name=None):
    """See base class for details."""
    # Restore names if defined
    filepath = _get_metadata_filepath(data_dir, feature_name)
    if tf.io.gfile.exists(filepath):
      with tf.io.gfile.GFile(filepath, 'r') as f:
        info_data = json.load(f)
      self.set_encoding_format(info_data['encoding_format'])
      self.set_shape([None if d == -1 else d for d in info_data['shape']])