public static function getList()
    {
        $app = Facade::getFacadeApplication();
        $db = $app->make('database')->connection();
        $libraries = [];
        foreach ($db->fetchAll('select sclHandle from SystemCaptchaLibraries order by sclHandle asc') as $row) {
            $scl = static::getByHandle($row['sclHandle']);
            $libraries[] = $scl;
        }

        return $libraries;
    }