python - 将弱引用转为强引用

Question

在我的代码中，标签对象被弱引用。我怎样才能把它变成强引用的？我收到错误“弱引用对象不再存在”。增加对该对象的引用会有所帮助吗？

from kivy.app import App
from kivy.core.audio import SoundLoader
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.uix.gridlayout import GridLayout

class Audioplayer(App):
    def build(self):
        layout = GridLayout(cols = 2 )
        btn = Button(text = "Arey Band kar")
        lbl = Label(text = "gaana ban Raha hai")

        music = SoundLoader.load("prb.mp3")

        if music:
            music.play()

        layout.add_widget(btn)
        layout.add_widget(lbl)

        return layout
        
Audioplayer().run()