def _change_brightness(self, step):
        """
        Control the change brightness logic for both
        decreasing and increasing.
        """
        # To limit the text displayed from float calcs
        self.brightness = round(self.brightness + step, 2)

        # ensure that brightness stays in the valid bounds
        if self.brightness < self.brightness_lower_lim:
            self.brightness = self.brightness_lower_lim
        elif self.brightness > self.brightness_upper_lim:
            self.brightness = self.brightness_upper_lim

        self.run_redshift()

        Control the change brightness logic for both
        decreasing and increasing.
        
libqtile/widget/redshift.py