windows - kivy button onstart info not working -

i'm beginning learn kivy on windows 10 machine. i've started small tutorials manly getting button display , event handler keep getting problems.

currently have following code

import kivy kivy.app import app kivy.uix.button import button kivy.uix.boxlayout import boxlayout kivy.logger import logger  class myapp(app):      def build(self):         return button(text='hello')      def on_start(self):         logger.info('app: i\'m alive!')  if __name__ == "__main__":     myapp().run() 

when go run windows command window opens closes before can read going on , nothing happens.

if remove def on_start method works ok , button displayed.

is there wrong code or install wrong , need again.