private function extractAuthEndpoint()
    {
        $auth = empty($this->config['auth_endpoint']) ? self::DEFAULT_AUTH_ENDPOINT : $this->config['auth_endpoint'];

        switch ($auth) {
            case Endpoint::UK:
                $endpoint = Rackspace::UK_IDENTITY_ENDPOINT;
                break;
            case Endpoint::US:
                $endpoint = Rackspace::US_IDENTITY_ENDPOINT;
                break;
            default:
                $endpoint = $auth;
                break;
        }

        return Url::factory($endpoint);
    }