def set_brightness(self, brightness):
        """set general brightness in range 0...1"""
        brightness = min([1.0, max([brightness, 0.0])]) # enforces range 0 ... 1
        self.state.brightness = brightness
        self._repeat_last_frame()
        sequence_number = self.zmq_publisher.publish_brightness(brightness)
        logging.debug("Set brightness to {brightPercent:05.1f}%".format(brightPercent=brightness*100))
        return (True, sequence_number, "OK")
set general brightness in range 0...1