Stripe Q39。I want to check the processing for the 'success_url' parameter of the 'Checkout \ Session :: create () method' in the Git-Hub code

The following PHP code works fine.

   $checkoutSession = \Stripe\Checkout\Session::create([

    'customer_email' => 'customer@example.com',

    'success_url' => 'https://xxxx/thanks.php',

The description is also described in the document.
The URL the customer will be directed to after the payment or subscription creation is successful.

But I want to see in PHP code how the process to be redirected to 'success_url' is implemented.
▼stripe-php /lib/Checkout/Session.php

<?php

namespace Stripe\Checkout;

/**

 * Class Session

 *

 * Omission

 *

 * @property string $success_url

 *

 * @package Stripe

 */

class Session extends \Stripe\ApiResource

{

    const OBJECT_NAME = "checkout.session";

    use \Stripe\ApiOperations\Create;

    use \Stripe\ApiOperations\Retrieve;

}

▼stripe-php /lib/ApiOperations/Create.php

trait Create

{

    /**

     * @param array|null $params

     * @param array|string|null $options

     *

     * @return \Stripe\ApiResource The created resource.

     */

    public static function create($params = null, $options = null)

    {

        self::_validateParams($params);

        $url = static::classUrl();

        list($response, $opts) = static::_staticRequest('post', $url, $params, $options);

        $obj = \Stripe\Util\Util::convertToStripeObject($response->json, $opts);

        $obj->setLastResponse($response);

        return $obj;

    }

}

Where is the process for 'success_url' implemented?

下記PHPコードは正常に動作する。

ドキュメントにも説明が記述されている。

しかし私は'success_url'へリダイレクトされる処理がどのように実装されているかをPHPコードで確認したい。

'success_url'に対する処理はどこで実装されているのですか？