/**
  * @param EventObserver $observer
  * @return void
  */
 public function execute(EventObserver $observer)
 {
     /** @var \Magento\Sales\Model\Order\Payment $orderPayment */
     $orderPayment = $observer->getEvent()->getPayment();
     $agreementCreated = false;
     if ($orderPayment->getBillingAgreementData()) {
         $order = $orderPayment->getOrder();
         /** @var \Magento\Paypal\Model\Billing\Agreement $agreement */
         $agreement = $this->agreementFactory->create()->importOrderPayment($orderPayment);
         if ($agreement->isValid()) {
             $message = __('Created billing agreement #%1.', $agreement->getReferenceId());
             $order->addRelatedObject($agreement);
             $agreement->addOrderRelation($order);
             $this->checkoutSession->setLastBillingAgreementReferenceId($agreement->getReferenceId());
             $agreementCreated = true;
         } else {
             $message = __('We can\'t create a billing agreement for this order.');
         }
         $comment = $order->addStatusHistoryComment($message);
         $order->addRelatedObject($comment);
     }
     if (!$agreementCreated) {
         $this->checkoutSession->unsLastBillingAgreementReferenceId();
     }
 }