public static function copyValues(array $keys, array $from, array $to, $force = false)
    {
        foreach ($keys as $key) {
            if (isset($from[$key])) {
                if ($force || !isset($to[$key])) {
                    $to[$key] = self::getValue($key, $from);
                }
            }
        }
        return $to;
    }