class Screen(object):    def __init__(self):        self._width = 0        self._height = 0    @property    def width(self):        return self._width    @property    def height(self):        return self._height    @width.setter    def width(self, value):        if not isinstance(value, (float, int)):            raise TypeError('width type must be float or int')        if value <= 0:            raise ValueError('width must be greater than zero')        self._width = value    @height.setter    def height(self, value):        if not isinstance(value, (float, int)):            raise TypeError('height type must be float or int')        if value <= 0:            raise ValueError('height must be greater than zero')        self._height = value    @property    def resolution(self):        return self._width * self._height