try again

    if os.path.exists(metadata_filename):

      tasks, metadata_df = load_from_disk(metadata_filename)

      del metadata_df['task_names']

      del metadata_df['basename']

      save_metadata(tasks, metadata_df, self.data_dir)

      return tasks, metadata_df

    raise ValueError("No Metadata Found On Disk")

    metadata_entries should have elements returned by write_data_to_disk

    above.

    """

    columns = ('basename', 'ids', 'X', 'y', 'w')

    columns = ('ids', 'X', 'y', 'w')

    metadata_df = pd.DataFrame(metadata_entries, columns=columns)

    return metadata_df