#!/usr/bin/env python3 # -*- coding: UTF-8 -*- class Meter(object): def __init__(self, value=0.0): self.value = float(value) def __get__(self, instance, owner): return self.value def __set__(self, instance, value): self.value = float(value) class Foot(object): def __get__(self, instance, owner): return instance.meter * 3.2808 def __set__(self, instance, value): instance.meter = float(value) / 3.2808 class Distance(object): meter = Meter() foot = Foot() if __name__ == '__main__': d = Distance() print(d.meter, d.foot) d.meter = 1 print(d.meter, d.foot) d.meter = 2 print(d.meter, d.foot)