protected static function unifyParams($type, $field, $default = '')
    {
        $data = array_column(self::$data[$type], $field);

        switch ($field) {
            case 'attr':
            case 'footer':
            case 'version':
                foreach ($data as $value) {
                    if ($data[0] !== $value) {
                        return $default;
                    }
                }
                return (isset($data[0]) && $data[0]) ? $data[0] : $default;
                
            default:
                $params = [];
                foreach ($data as $value) {
                    $params = array_merge($params, $value);
                }

                return array_unique($params);
        }
    }