Update Article.php

Author: Swader

src/Entity/Article.php

@@ -61,6 +61,9 @@ public function getHtml()
      */
     public function getDate()
     {
+        if (!isset($this->data['date'])) {
+            return null;
+        }
         return (class_exists('\Carbon\Carbon')) ?
             new \Carbon\Carbon($this->data['date'], 'GMT') :
             $this->data['date'];
@@ -268,4 +271,4 @@ public function getEstimatedDate()
             new \Carbon\Carbon($date, 'GMT') :
             $date;
     }
-}
+}