from gi.repository import Notify
import time

time.sleep(5)

Notify.init('notification-count-test')
notification = Notify.Notification.new(
        'a',
        'a',
        'dialog-information'
    )
notification.show()

notification2 = Notify.Notification.new(
        'a',
        'a',
        'dialog-information'
    )
notification2.show()
