pagelayout在py中的引用不支持size_hint和pos_hint

from kivy.uix.pagelayout import PageLayout
from kivy.uix.button import Button
from kivy.app import App

class PageLayoutWidget(PageLayout):
    def __init__(self,**kwargs):
        super().__init__(**kwargs)

        bt0 = Button(text='bt0',background_color=[.3,.9,.3,1])
        bt1 = Button(text='bt1',background_color=[.9,.3,.3,1])

        self.add_widget(bt0)
        self.add_widget(bt1)

class PageLayoutApp(App):
    def build(self):
        return PageLayoutWidget()

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