protected function createTranslationNode(\DOMDocument $dom, $id, $key, $value)
    {
        $translationNode = $dom->createElement('trans-unit');
        $translationNode->appendChild(new \DOMAttr('id', $id));
        
        /**
         * @see http://docs.oasis-open.org/xliff/v1.2/os/xliff-core.html#approved
         */
        if ($value != '') {
            $translationNode->appendChild(new \DOMAttr('approved', 'yes'));
        }

        $source = $dom->createElement('source');
        $source->appendChild($dom->createCDATASection($key));
        $translationNode->appendChild($source);

        $target = $dom->createElement('target');
        $target->appendChild($dom->createCDATASection($value));
        $translationNode->appendChild($target);

        return $translationNode;
    }