public static function formatKey($key, $options = null)
    {
        $options = Helper::getOptions($options, [
            "underscores"   =>  true,
            "ucwords"       =>  true,
        ]);

        if ($options["underscores"]) {
            $val = str_replace("_", "&nbsp;", $key);
        }

        if ($options["ucwords"]) {
            $val = ucwords($val);
        }

        return $val;
    }