diff --git a/src/Passbook/PassInterface.php b/src/Passbook/PassInterface.php
index 95d7b85..28e7904 100644
--- a/src/Passbook/PassInterface.php
+++ b/src/Passbook/PassInterface.php
@@ -232,7 +232,7 @@ public function getLogoText();
     /**
      * {@inheritdoc}
      */
-    public function setSharingProhibited($sharingProhibited);
+    public function setSharingProhibited(bool $sharingProhibited);
 
     /**
      * {@inheritdoc}