PayPal\Api\ItemList::setItems PHP Method

    public function setItems($items)
    {
        $this->items = $items;
        return $this;
    }

 /**
  * @return Payment
  * @throws CheckoutException
  */
 public function startPayment()
 {
     $total_amount = ($this->request->amount + $this->request->tax_amount - $this->request->discount_amount) * 100;
     $apiContext->setConfig(array('service.EndPoint' => "https://test-api.sandbox.paypal.com"));
     $payer = new Payer();
     $payer->setPaymentMethod('paypal');
     $item1 = new Item();
     $item1->setName('Product1')->setCurrency('EUR')->setPrice(10.0)->setQuantity(2)->setTax(3.0);
     $itemList = new ItemList();
     $itemList->setItems(array($item1));
     $details = new Details();
     $details->setShipping(1.2)->setTax(1.3)->setSubtotal(17.5);
     $amount = new Amount();
     $amount->setCurrency('EUR')->setTotal(20)->setDetails($details);
     $transaction = new Transaction();
     $transaction->setAmount($amount)->setItemList($itemList)->setDescription('Payment')->setInvoiceNumber('transactionid');
     $baseUrl = getBaseUrl();
     $redir = new RedirectUrls();
     $redir->setReturnUrl($baseUrl . '/');
     $redir->setCancelUrl($baseUrl . '/');
     $payment = new Payment();
     $payment->setIntent('sale')->setPayer($payer)->setRedirectUrls($redir)->setTransactions(array($transaction));
     $request = clone $payment;
     try {
         $payment->create($apiContext);
     } catch (\Exception $e) {
         throw new CheckoutException('Paypal error', 500, $e);
     }
     $approvalUrl = $payment->getApprovalLink();
     ResultPrinter::printResult("Created Payment Using PayPal. Please visit the URL to Approve.", "Payment", "<a href='{$approvalUrl}' >{$approvalUrl}</a>", $request, $payment);
     return $payment;
 }