diff --git a/subjects/listlast.en.md b/subjects/listlast.en.md
index 273d3ef6..e46d0aa8 100644
--- a/subjects/listlast.en.md
+++ b/subjects/listlast.en.md
@@ -17,7 +17,7 @@ type List struct {
 	Tail *Node
 }
 
-func ListLast(l *List) *List {
+func ListLast(l *List) interface{} {
 }
 ```