def set_ds9(self, level="PREF"):
        """
        Set the default values on the ds9 display.
        """
        self.set_zoom()
        ds9_settings = config.read("DS9."+level)
        for key in ds9_settings.keys():
            value = ds9_settings[key]
            cmd = key.replace("_", " ")
            self.ds9.set("{} {}".format(cmd, value))
Set the default values on the ds9 display.