@property

from math import pi
class Circle:
    def __init__(self,r):
        self.r = r
    @property
    def mianji(self):
        return pi*self.r**2
    @property    #将方法用装饰器伪装成属性
    def zhou(self):
        return 2*pi*self.r

c = Circle(5)
print(c.mianji)