Python kivy:无法在on_press中传递数据

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

class MyApp(App):
    def build(self):
        button = Button(text='Click me')
        button.bind(on_press=lambda instance: self.on_button_press(instance, 'Hello Kivy'))
        return button

    def on_button_press(self, instance, data):
        print(data)

MyApp().run()

from kivy.app import App
from kivy.uix.button import Button
from functools import partial

class MyApp(App):
    def build(self):
        button = Button(text='Click me')
        button.bind(on_press=partial(self.on_button_press, data='Hello Kivy'))
        return button

    def on_button_press(self, instance, data):
        print(data)

MyApp().run()