How to use the dtaidistance.dtw_weighted.plot_margins function in dtaidistance

def plot_margins(serie, weights, clfs, importances=None):
    global directory
    if directory is None:
        directory = prepare_directory()
    from sklearn import tree
    feature_names = ["f{} ({}, {})".format(i // 2, i, '-' if (i % 2) == 0 else '+') for i in range(2 * len(serie))]
    out_str = io.StringIO()
    for clf in clfs:
        tree.export_graphviz(clf, out_file=out_str, feature_names=feature_names)
        print("\n\n", file=out_str)
    with open(str(directory / "tree.dot"), "w") as ofile:
        print(out_str.getvalue(), file=ofile)
    dtww.plot_margins(serie, weights, filename=str(directory / "margins.png"), importances=importances)