private function configCache(): ConfigCache
    {
        if (null === $this->configCache)
        {
            $this->configCache = new ConfigCache($this->getContainerClassPath(), $this->environment->isDebug());
        }

        return $this->configCache;
    }
private function configCache(): ConfigCache
    {
        if (null === $this->configCache)
        {
            $this->configCache = new ConfigCache($this->getContainerClassPath(), $this->environment->isDebug());
        }

        return $this->configCache;
    }
private function configCache ( ) : ConfigCache { if ( null === $ this -> configCache ) { $ this -> configCache = new ConfigCache ( $ this -> getContainerClassPath ( ) , $ this -> environment -> isDebug ( ) ) ; } return $ this -> configCache ; }
Receive config cache.

@return ConfigCache
Receive config cache .