protected function getCacheContent($key = null)
    {
        if (!$this->cache instanceof CacheInterface) {
            return false;
        }
        if (isset($key) && ($result = $this->cache->get($key)) !== false) {
            if (is_array($result) && isset($result['placeholders'], $result['result'])) {
                $this->addMultiPlaceholders($result['placeholders']);
                $result = $result['result'];
            }

            return $result;
        }

        return false;
    }