ScatterLayout分散布局在kv中的引用

from kivy.uix.scatterlayout import ScatterLayout
from kivy.app import App

class ScatterLayoutWidget(ScatterLayout):
    def __init__(self,**kwargs):
        super().__init__(**kwargs)

class ScatterLayoutApp(App):
    def build(self):
        return ScatterLayoutWidget()

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

================kv段=============

<ScatterLayoutWidget>:
    canvas:
        Color:
            rgba:[1,1,1,1]
        Rectangle:
            size:self.size
            pos:self.pos
    ScatterLayout:
        Image:
            source:'1.jpg'