public static function mergeFlags(Translation $from, Translation $to, $options = self::DEFAULTS)
    {
        if ($options & self::FLAGS_THEIRS) {
            $to->deleteFlags();
        }

        if (!($options & self::FLAGS_OURS)) {
            foreach ($from->getFlags() as $flag) {
                $to->addFlag($flag);
            }
        }
    }