diff --git a/racket/typed/examples/roles/book-club.rkt b/racket/typed/examples/roles/book-club.rkt
index 724706a..ace718b 100644
--- a/racket/typed/examples/roles/book-club.rkt
+++ b/racket/typed/examples/roles/book-club.rkt
@@ -47,8 +47,8 @@
 
 (define (lookup [title : String]
                 [inv : Inventory] -> Int)
-  (for/fold [stock 0]
-            [item inv]
+  (for/fold ([stock 0])
+            ([item inv])
     (if (equal? title (select 0 item))
         (select 1 item)
         stock)))