diff --git a/modules/preprodwarning/lib/Auth/Process/Warning.php b/modules/preprodwarning/lib/Auth/Process/Warning.php
index bbc6fdadb2d20f684c75db19e17f5e7419dce5bf..6a7c7925d100c0b3393981993b8318e1fd0f5dd5 100644
--- a/modules/preprodwarning/lib/Auth/Process/Warning.php
+++ b/modules/preprodwarning/lib/Auth/Process/Warning.php
@@ -17,6 +17,7 @@ class Warning extends \SimpleSAML\Auth\ProcessingFilter
      * can authorize the release of the attributes.
      *
      * @param array $state  The state of the response.
+     * @return void
      */
     public function process(&$state)
     {