/**
  * Return billing agreement information
  *
  * @return string
  */
 protected function _toHtml()
 {
     $agreementReferenceId = $this->_checkoutSession->getLastBillingAgreementReferenceId();
     $customerId = $this->_customerSession->getCustomerId();
     if (!$agreementReferenceId || !$customerId) {
         return '';
     }
     $agreement = $this->_agreementFactory->create()->load($agreementReferenceId, 'reference_id');
     if ($agreement->getId() && $customerId == $agreement->getCustomerId()) {
         $this->addData(['agreement_ref_id' => $agreement->getReferenceId(), 'agreement_url' => $this->getUrl('paypal/billing_agreement/view', ['agreement' => $agreement->getId()])]);
         return parent::_toHtml();
     }
     return '';
 }