class Screen(object):

@property
def width(self):
    return self._width#起名加下划线是为了避免递归调用自己
@width.setter
def width(self,value):
    self._width=value

@property
def height(self):
    return self._height
@height.setter
def height(self,value):
    self._height=value

@property
def resolution(self):
    return self.height*self.width

s = Screen() s.width=1024 s.height=768 print('resolution = ',s.resolution) if s.resolution == 786432: print('ok') else: print("not")