code: def load_metadata(self, data_dir, feature_name=None):
      
      # 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']])
docs: See base class for details.