保存Kivy对象

Question

我试图腌制一个kivy对象，但我收到了以下错误：

TypeError: can't pickle hands_screen objects

这是我的代码：

class ranges_app(App):
    def build(self):
        return screen()
    def pickle_object(self, name, obj):
        with open(name + '.pickle', 'wb') as f:
            pickle.dump(obj, f, protocol = pickle.HIGHEST_PROTOCOL)
    def on_stop(self):
        app = App.get_running_app()
        f = app.root.manager.utg
        print(f.name)
        self.pickle_object(f.name, f.h)

class big_screen(Screen):
    def __init__(self, **kwargs):
        super(big_screen, self).__init__(**kwargs)
        self.h = hands_screen()
        self.add_widget(self.h)

class hands_screen(GridLayout):
    def __init__(self, **kwargs):
        super(hands_screen, self).__init__(**kwargs)
        self.l = ['A', 'K', 'Q', 'J', 'T'] + [str(i) for i in range(9,1,-1)]
        self.cols = 13
        self.rows = 13
        for i in range(13):
            for j in range(13):
                self.add_widget(hand_button(text = [str(self.l[i])+str(self.l[j]) + 's', str(self.l[j]) + str(self.l[i])+'o', str(self.l[j]) + str(self.l[i])][(i>j) - (i == j)]))

有没有办法解决这个错误或一般保存一个kivy对象？