diff --git a/features/help.feature b/features/help.feature
index 1a3c03de32..a306e9b755 100644
--- a/features/help.feature
+++ b/features/help.feature
@@ -475,7 +475,7 @@ Feature: Get help about WP-CLI commands
         function __sleep() {}
         function __wakeup() {}
         function __toString() {}
-        function __set_state() {}
+        function __set_state( $properties ) {}
         function __clone() {}
         function __debugInfo() {}
       }