public static function prefixSlug(string $slug) : string
    {
        if (substr($slug, 0, strlen(self::MODULE_PREFIX)) !== self::MODULE_PREFIX) {
            $slug = self::MODULE_PREFIX . $slug;
        }

        if (strlen($slug) > 20) {
            $slug = substr($slug, 0, 20);
        }

        $slug = strtolower($slug);

        return $slug;
    }