diff --git a/src/Events.php b/src/Events.php
index 5bd839c..b41b5bb 100644
--- a/src/Events.php
+++ b/src/Events.php
@@ -74,7 +74,7 @@ protected function assertValidEvent(string $event): void
      *
      * @return bool
      */
-    public function isValidEvent($event)
+    public function isValidEvent(string $event): bool
     {
         return true;
     }