python中的属性依赖项和更新

class Rectangle:
    def __init__(self, width, height):
        self._width = width
        self._height = height
    
    @property
    def width(self):
        return self._width
    
    @width.setter
    def width(self, value):
        self._width = value
        self._update_area()
    
    @property
    def height(self):
        return self._height
    
    @height.setter
    def height(self, value):
        self._height = value
        self._update_area()
    
    def _update_area(self):
        self._area = self._width * self._height
    
    @property
    def area(self):
        return self._area


rect = Rectangle(5, 10)
print(rect.area)  # 输出：50

rect.width = 7
print(rect.area)  # 输出：70

rect.height = 15
print(rect.area)  # 输出：105