from functools import cached_property

class Person:
    def __init__(self, height, bmi):
        self.height = height
        self.bmi = bmi

    @cached_property
    def weight(self):
        print("====正在执行复杂计算====")
        return self.height ** 2 * self.bmi


p = Person(1.75, 22)

# 第一次访问：执行函数，打印日志，保存结果
print(p.weight)
# 第二次访问：直接读缓存！不会打印日志，不重新计算
print(p.weight)
print(p.weight)


class Person2:
    def __init__(self, height, bmi):
        self.height = height
        self.bmi = bmi

    @property
    def weight(self):
        print("====每次都重新计算====")
        return self.height ** 2 * self.bmi

p2 = Person2(1.75,22)
print(p2.weight)
print(p2.weight)