def groups_option(f):
    new_func = click.option("-g", "--groups",
                            help="Comma-separated list of requirement groups "
                            "to include.")(f)
    return update_wrapper(new_func, f)
def allowed_file(filename):
    return '.' in filename and \
           filename.rsplit('.', 1)[1] in app.config.get('ALLOWED_EXTENSIONS')