描述符——类型检测，待补充……

先看代码：

 1 # 描述的类
 2 class Check(object):
 3     def __init__(self, key, value_type):
 4         self.k = key
 5         self.t = value_type
 6 
 7     def __set__(self, instance, value):
 8         print('set方法...')
 9         if isinstance(value, self.t):
10             instance.__dict__[self.k] = value
11         else:
12             raise TypeError('传入格式错误！')
13 
14     def __get__(self, instance, owner):
15         print('get方法...')
16         return instance.__dict__[self.k]
17 
18     def __delete__(self, instance, owner):
19         print('delete方法...')
20         return instance.__dict__.pop(self.k)
21 
22 
23 class C(object):
24     name = Check('name', str)
25     age = Check('age', int)
26 
27     def __init__(self, name, age):
28         self.name = name
29         self.age = age
30 
31 c1 = C('aa',12)
32 c1.name='cname'
33 print(c1.name)