Сумма класса не найдена PayPal

<?php
require("/includes/db.php");

$q = $db->prepare("SELECT * FROM products ORDER BY RAND() LIMIT 0,1");
$q->execute();

$product = $q->fetch(PDO::FETCH_OBJ);

require("PayPal-PHP-SDK/autoload.php");
$ids = require("/includes/paypal.php");

$apiContext = new PayPal\Rest\ApiContext(
	new \PayPal\Auth\OAuthTokenCredential(
		$ids["id"],
		$ids["secret"]
	)
);

$list = new \PayPal\Api\ItemList();

$item = (new \PayPal\Api\Item())
	->setName($product->name)
	->setPrice($product->price)
	->setCurrency('EUR')
	->setQuantity(1);

$details = (new \PayPal\Api\Details())
	->setSubTotal($item->price);

$list->addItem($item);

$amount = (new \Paypal\Api\Amount())
	->setTotal($item->price)
	->setCurrency("EUR")
	->setDetails($details);

$transaction = (new \Paypal\Api\Transaction())
	->setItemList($list)
	->setDescription($product->product_desc)
	->setAmount($amount)
	->setCustom($product->product_id);

$payment = (new \PayPal\Api\Payment())
	->setIntent("sale");

$redirect_urls = (new \PayPal\Api\RedirectUrls())
	->setReturnUrl("http://localhost:8000/pay.php")
	->setReturnUrl("http://localhost:8000/index.php");

$payment->setRedirectUrls($redirect_urls);
$payment->setTransaction([$transaction]);
$payment->setPayer((new PayPal\Api\Payer())->setPaymentMethod("paypal"));

echo $payment->getApprovalLink();