diff --git a/Models/NewsArticle.php b/Models/NewsArticle.php
index 974e537..78aa99d 100755
--- a/Models/NewsArticle.php
+++ b/Models/NewsArticle.php
@@ -374,7 +374,7 @@ class NewsArticle implements \JsonSerializable, ArrayableInterface
     /**
      * {@inheritdoc}
      */
-    public function jsonSerialize()
+    public function jsonSerialize() : mixed
     {
         return $this->toArray();
     }