def get_feature_set():
    """
    Return a list of features' names.

    Features' name that are used to train a model and predict a class.
    Sorted by the names.

    Returns
    -------
    feature_names : list
        A list of features' names.
    """
    features = ['amplitude', 'hl_amp_ratio', 'kurtosis', 'period',
        'phase_cusum', 'phase_eta', 'phi21', 'phi31', 'quartile31', 'r21',
        'r31', 'shapiro_w', 'skewness', 'slope_per10', 'slope_per90',
        'stetson_k']
    features.sort()
    return features
