在之前，我们介绍过装饰器的用法：
    装饰器

    装饰器可以动态给函数增加功能，对于class，Python内置的@property装饰器也能对 对象的属性进行增强

    1. class Student(object):
    2.     @property
    3.     def score(self):
    4.         return self._score
    5.     @score.setter
    6.     def score(self, value):
    7.         if not isinstance(value, int):
    8.             raise ValueError('score must be an integer!')
    9.         if value < 0 or value > 100:
    10.             raise ValueError('score must between 0 ~ 100!')
    11.         self._score = value
    1. >>> s = Student()
    2. >>> s.score = 60 
    3. >>> s.score
    4. 60
    5. >>> s.score = 9999
    6. Traceback (most recent call last):
    7.   ...
    8. ValueError: score must between 0 ~ 100!