public function unregister($providerClass)
    {
        $providers = $this->getOption(self::OPTION_PROVIDERS);
        foreach ($providers as $key => $provider) {
            if (get_class($provider) == $providerClass) {
                unset($providers[$key]);
            }
        }
        $this->setOption(self::OPTION_PROVIDERS, $providers);
    }