public function getSiblingNode()
    {
        if ($this->siblingDomAddress === null) {
            return null;
        }

        if ($this->cachedSiblingNode === null) {
            $this->cachedSiblingNode = $this->nodeService->getNodeFromContextPath(
                $this->siblingDomAddress->getContextPath()
            );
        }

        return $this->cachedSiblingNode;
    }