How to use the vorta.models.SettingsModel.get function in vorta

def save_setting(self, key, new_value):
        setting = SettingsModel.get(key=key)
        setting.value = bool(new_value)
        setting.save()

        if key == 'autostart':
            open_app_at_startup(new_value)

import objc
        import Cocoa
        bundle_path = os.path.join(os.path.dirname(sys.executable), os.pardir, 'Frameworks', 'Sparkle.framework')
        objc.loadBundle('Sparkle', globals(), bundle_path)
        sparkle = SUUpdater.sharedUpdater()  # noqa: F821

        # A default Appcast URL is set in vorta.spec, when setting it here it's saved to defaults,
        # so we need both cases.
        if SettingsModel.get(key='updates_include_beta').value:
            appcast_nsurl = Cocoa.NSURL.URLWithString_('https://borgbase.github.io/vorta/appcast-pre.xml')
        else:
            appcast_nsurl = Cocoa.NSURL.URLWithString_('https://borgbase.github.io/vorta/appcast.xml')

        sparkle.setFeedURL_(appcast_nsurl)

        if SettingsModel.get(key='check_for_updates').value:
            sparkle.setAutomaticallyChecksForUpdates_(True)
            sparkle.checkForUpdatesInBackground()

        sparkle.setAutomaticallyDownloadsUpdates_(False)
        return sparkle

    else:  # TODO: implement for Linux
        return None

def notifications_suppressed(self, level):
        """Decide if notification is sent or not based on settings and level."""
        if not SettingsModel.get(key='enable_notifications').value:
            logger.debug('notifications suppressed')
            return True
        if level == 'info' and not SettingsModel.get(key='enable_notifications_success').value:
            logger.debug('success notifications suppressed')
            return True

        logger.debug('notification not suppressed')
        return False

def get_theme_class():
    """
    Choose a package to import collection_rc from.

    light = white icons, dark = black icons.

    Defaults to dark icons (light theme) if DB isn't initialized yet.
    """
    if SettingsModel._meta.database.obj is None:
        return 'vorta.views.dark'
    else:
        use_light_icon = SettingsModel.get(key='use_dark_theme').value
        return 'vorta.views.light' if use_light_icon else 'vorta.views.dark'

def set_tray_icon(tray, active=False):
    from vorta.models import SettingsModel
    use_light_style = SettingsModel.get(key='use_light_icon').value
    icon_name = f"icons/hdd-o{'-active' if active else ''}-{'light' if use_light_style else 'dark'}.png"
    icon = QIcon(get_asset(icon_name))
    tray.setIcon(icon)