有没有办法在Kivy中画一条横跨整个Widget的垂直线？

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.graphics import Line

class MyWidget(Widget):
    def __init__(self, **kwargs):
        super(MyWidget, self).__init__(**kwargs)
        with self.canvas:
            # 绘制一条垂直线，起点为(0, 0)，终点为(0, self.height)
            Line(points=[self.x, self.y, self.x, self.height])

class MyApp(App):
    def build(self):
        return MyWidget()

if __name__ == '__main__':
    MyApp().run()