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 memoized(*args):
        try:
            return stored_results[args]
        except KeyError:
            result = stored_results[args] = fn(*args)
            return result