public static function mergeComments(Translation $from, Translation $to, $options = self::DEFAULTS)
    {
        if ($options & self::COMMENTS_THEIRS) {
            $to->deleteComments();
        }

        if (!($options & self::COMMENTS_OURS)) {
            foreach ($from->getComments() as $comment) {
                $to->addComment($comment);
            }
        }
    }