def OnTimeToClose(self, evt):
        """Event handler for the button click."""
        print("See ya later!")
        sys.stdout.flush()
        self.cleanup_consoles(evt)
        self.Close()
        # Not sure why, but our IPython kernel seems to prevent normal WX
        # shutdown, so an explicit exit() call is needed.
        sys.exit()
Event handler for the button click.