public function injectObjectManager(ObjectManagerInterface $objectManager): void
    {
        if ($this->objectManager === null) {
            $this->objectManager = $objectManager;
            /** @var CacheManager $cacheManager */
            $cacheManager = $this->objectManager->get(CacheManager::class);
            $this->runtimeExpressionsCache = $cacheManager->getCache('Flow_Aop_RuntimeExpressions');
        }
    }