def want_sleep(self) -> None:
        """
        Convenience method to set flag to show we want to know when the
        system is going down for sleep.
        """
        if not has_dbus:
            logger.warning("dbus-fast must be installed to listen to sleep signals")
        self.sleep = True

        Convenience method to set flag to show we want to know when the
        system is going down for sleep.
        
libqtile/resources/sleep.py