protected function getNormalizedConfig($configName = null)
    {
        if (isset($this->configs[$configName])) {
            $config = $this->configs[$configName];
        } elseif ($configName === null) {
            $arr = array();
            $config = $this->normalizeConfig($arr);
        } else {
            throw new \Exception(sprintf('Firewall configuration "%s" not found.', $configName));
        }

        return $config;
    }