diff --git a/src/Props/Container.php b/src/Props/Container.php
index 9e48548..7327477 100644
--- a/src/Props/Container.php
+++ b/src/Props/Container.php
@@ -102,7 +102,7 @@ public function __isset($name)
     /**
      * {@inheritdoc}
      */
-    public function has($name)
+    public function has($name): bool
     {
         return $this->__isset($name);
     }