从Paypal REST API协议获取信用卡ID

Question

Hi am setting up an automatic billing agreement on PayPal

The code works:

$apiContext = new \PayPal\Rest\ApiContext(new \PayPal\Auth\OAuthTokenCredential($this->CLIENT_ID, $this->CLIENT_SECRET));

    $agreement = new Agreement();

    $agreement->setName('Agreement')
        ->setDescription('Base Plan')
        ->setStartDate('2015-06-01T12:00:00Z');

    $plan = new Plan();
    $plan->setId($planID);
    $agreement->setPlan($plan);

    // Add Payer
    $payer = new Payer();
    $payer->setPaymentMethod('credit_card')->setPayerInfo(new PayerInfo(array(
        'email' => $email
    )));

    // Add Credit Card to Funding Instruments
    $creditCard = new CreditCard();
    $creditCard->setType($cctype)
        ->setNumber($ccnumber)
        ->setExpireMonth($ccexpirymonth)
        ->setExpireYear($ccexpiryyear)
        ->setCvv2($ccv);






    $fundingInstrument = new FundingInstrument();
    $fundingInstrument->setCreditCard($creditCard);



    $payer->setFundingInstruments(array(
        $fundingInstrument
    ));
    // Add Payer to Agreement
    $agreement->setPayer($payer);

    $shippingAddress = new ShippingAddress();
    $shippingAddress->setLine1('111 First Street')
        ->setCity('Saratoga')
        ->setState('CA')
        ->setPostalCode('95070')
        ->setCountryCode('US');
    $agreement->setShippingAddress($shippingAddress);

    try {

        $createagreement = $agreement->create($apiContext);


    } catch (Exception $ex) {




        exit(1);
    }

What I am trying to get is the credit card ID that PayPal should have so that some information about the credit card can be used later for updating the credit card at a later time etc.

I thought:

$creditCard->getId(); 

would work, but it does not return anything,

How can I get the Credit Card ID?