我在Android上打开应用程序，这个应用程序崩溃了。为什么呢？（Kivy）

Question

我写得不对吗？打开应用程序后，Android设备必须振动，但在应用程序打开后，它会崩溃。为什么我的kivy应用程序崩溃了？代码：

from plyer import vibrator
from kivy.app import App
from kivy.properties import StringProperty
from kivy.clock import Clock, mainthread
from kivy.uix.floatlayout import FloatLayout #the UI layout
from kivy.uix.label import Label #a label to show information
class UI(FloatLayout):
    """docstring for UI"""
    def __init__(self):
        super(UI, self).__init__()

        self.lblAcce = Label(text="Vibrate: ") #create a label at the center
        self.add_widget(self.lblAcce) #add the label at the screen
        time = 2
        try:
            vibrator.vibrate(time=time)
            #if you want do disable it, just run: accelerometer.disable()
            Clock.schedule_interval(self.update, 1.0/24) #24 calls per second
        except:
            self.lblAcce.text = "Failed to start vibrate" #error
class Vibrate(App): #our app
    def build(self):
        ui = UI()# create the UI
        return ui #show it

if __name__ == '__main__':
    Vibrate().run() #start our app