public function cloneChildrenFrom(SimpleXMLElement $src, $deep = true)
    {
        $src = dom_import_simplexml($src);
        $dst = dom_import_simplexml($this);
        $doc = $dst->ownerDocument;

        $fragment = $doc->createDocumentFragment();
        foreach ($src->childNodes as $child) {
            $fragment->appendChild($doc->importNode($child->cloneNode($deep), $deep));
        }
        $dst->appendChild($fragment);

        return $this;
    }