装饰器前面提过了，采用python的闭包特性实现：

from time import timefrom time import sleepdef count_time():    def tmp(func):        def wrapped(*args, **kargs):            begin_time = time()            result = func(*args, **kargs)            end_time = time()            cost_time = end_time - begin_time            print '%s called cost time : %s' %(func.__name__, cost_time)            return result        return wrapped    return tmp@count_time()def test():    sleep(0.5)if __name__ == '__main__':    test()

我们尝试以下的代码：

class Test:    @count_time()    def test(self):        print 'haha'if __name__ == '__main__':#    test()    a = Test()    a.test()

代码仍然可以正常工作，因为a.test()仅仅就是给test添加了一个额外的参数a而已。