下面格式错了，重来 **手动捂脸

def log(*arg_list):
    if isinstance(arg_list[0], str):
        text = arg_list[0]
        def decorator(func):
            def wrapper(*args, **kw):
                print('%s %s():' % (text, func.__name__))
                return func(*args, **kw)
            return wrapper
        return decorator
    else:
        func = arg_list[0]
        def wrapper(*args, **kw):
            print('call %s():' % func.__name__)
            return func(*args, **kw)
        return wrapper

@log

def now(): print('test')

now()

# 结果
call now():
test

@log('123')

def now(): print('test')

now()

# 结果
123 now():
test