def creep_data(data_set='creep_rupture'):
    """Brun and Yoshida's metal creep rupture data."""
    if not data_available(data_set):
        download_data(data_set)
        path = os.path.join(data_path, data_set)
        tar_file = os.path.join(path, 'creeprupt.tar')
        tar = tarfile.open(tar_file)
        print('Extracting file.')
        tar.extractall(path=path)
        tar.close()
    all_data = np.loadtxt(os.path.join(data_path, data_set, 'taka'))
    y = all_data[:, 1:2].copy()
    features = [0]
    features.extend(range(2, 31))
    X = all_data[:, features].copy()
    return data_details_return({'X': X, 'y': y}, data_set)