protected function getXPath()
    {
        if (!$this->xpath) {
            $this->xpath = new \DOMXPath($this->getDomElement()->ownerDocument);
            $namespaces = $this->getExtensions()->getNamespaces();
            foreach ($namespaces as $prefix => $namespace) {
                $this->xpath->registerNamespace($prefix, $namespace);
            }
        }

        return $this->xpath;
    }