public function authentications( ThreeDSecure\Authentications $authentications )
    {
        $authentications->setRequiredFields(array(
            'merchantRefNum',
            'paRes'
        ));
        $authentications->checkRequiredFields();
        $request = new Request(array(
            'method' => Request::POST,
            'uri' => $this->prepareURI("/enrollmentchecks/" . $authentications->id . "/authentications"),
            'body' => $authentications
        ));

        $response = $this->client->processRequest($request);
        return new ThreeDSecure\Authentications($response);
    }