diff --git a/src/koans/04_sets.clj b/src/koans/04_sets.clj
index 256bd47..ffd1738 100644
--- a/src/koans/04_sets.clj
+++ b/src/koans/04_sets.clj
@@ -15,4 +15,4 @@
   (= __ (clojure.set/intersection #{1 2 3 4} #{2 3 5}))
 
   "But don't forget about the difference"
-  (= __ (clojure.set/difference #{1 2 3 4 5} #{2 3 5})))
+  (= __ (clojure.set/difference #{1 2 3 4 5} #{2 3 5}))