public function getMessageHelperService()
    {
        if ($this->messageHelperService === null) {
            $this->messageHelperService = new MessageHelperService(
                $this->getPartBuilderFactory()
            );
            $this->messageHelperService->setPartFactoryService(
                $this->getPartFactoryService()
            );
        }
        return $this->messageHelperService;
    }