diff --git a/lens/base/transform.rkt b/lens/base/transform.rkt
index 0ea3f7e..7909070 100644
--- a/lens/base/transform.rkt
+++ b/lens/base/transform.rkt
@@ -7,10 +7,15 @@
   (require rackunit
            fancy-app))
 
-(provide lens-transform
-         lens-transform*)
+(provide
+ lens-transform*
+ (contract-out [lens-transform (-> lens? any/c (-> any/c any/c) any/c)]))
+               
 
 
+(define (listof* . contracts)
+  (or/c '() (apply list/c (append contracts (list (apply listof* contracts))))))
+                                     
 (define (lens-transform lens v f)
   (let-lens (view setter) lens v
     (setter (f view))))