class Screen(object): @property def width(self): return self._width @property def height(self): return self._height @width.setter def width(self,value): self._width=value @height.setter def height(self,value): self._height=value @property def resolution(self): return self._width*self._height s=Screen() s.width=1024 s.height=768 print('resolution=',s.resolution)