public static function setActiveTheme($code)
    {
        self::resetCache();

        Parameter::set(self::ACTIVE_KEY, $code);

        /**
         * @event cms.theme.setActiveTheme
         * Fires when the active theme has been changed.
         *
         * If a value is returned from this halting event, it will be used as the active
         * theme code. Example usage:
         *
         *     Event::listen('cms.theme.setActiveTheme', function($code) {
         *         \Log::info("Theme has been changed to $code");
         *     });
         *
         */
        Event::fire('cms.theme.setActiveTheme', compact('code'));
    }