diff --git a/library/Businessprocess/Renderer/Renderer.php b/library/Businessprocess/Renderer/Renderer.php
index 6aa1363..6a5d624 100644
--- a/library/Businessprocess/Renderer/Renderer.php
+++ b/library/Businessprocess/Renderer/Renderer.php
@@ -169,7 +169,7 @@ abstract class Renderer extends HtmlDocument
 
     /**
      * @param $summary
-     * @return BaseHtmlElement
+     * @return ?BaseHtmlElement
      */
     public function renderStateBadges($summary, $totalChildren)
     {