diff --git a/Controller/tpay/Notification.php b/Controller/tpay/Notification.php
index dbfde00..1b46fdf 100644
--- a/Controller/tpay/Notification.php
+++ b/Controller/tpay/Notification.php
@@ -106,7 +106,10 @@ public function execute()
      *
      * @return null|InvalidRequestException
      */
-    public function createCsrfValidationException(RequestInterface $request) {}
+    public function createCsrfValidationException(RequestInterface $request): ?InvalidRequestException
+    {
+        return null;
+    }
 
     /**
      * Perform custom request validation.
@@ -114,7 +117,7 @@ public function createCsrfValidationException(RequestInterface $request) {}
      *
      * @return null|bool
      */
-    public function validateForCsrf(RequestInterface $request)
+    public function validateForCsrf(RequestInterface $request): ?bool
     {
         return true;
     }