Kivy use Android Notifications
Since you've changed your topic to android...I can help!
Kivy has a sister project, plyer, providing a platform independent way to access different apis through a single pythonic interface. There are quite a few interfaces implemented for Android, including notifications, so you can use plyer directly and/or look at the code to see how it works.
As it happens I've previously made a short video about the android stuff, which you can find here. It's only a very quick introduction, but might help.
I hope this will help you.
import kivy.app
import plyer
class PushNotificationApp(kivy.app.App):
def show_notification(self):
plyer.notification.notify(title='test', message="Notification using plyer")
app = PushNotificationApp()
app.run()