FluentDOM\Loader\PHP\SimpleXml::loadFragment PHP Method

    public function loadFragment($source, $contentType, $options = [])
    {
        if (!$this->supports($contentType)) {
            return NULL;
        } elseif (is_string($source)) {
            $this->_xmlLoader = $this->_xmlLoader ?: new Xml();
            return $this->_xmlLoader->loadFragment($source, 'text/xml');
        } elseif ($source instanceof \SimpleXMLElement) {
            $node = dom_import_simplexml($source);
            $fragment = $node->ownerDocument->createDocumentFragment();
            $fragment->appendChild($node->cloneNode(TRUE));
            return $fragment;
        }
        throw new InvalidArgument('source', ['SimpleXMLElement', 'string']);
    }