diff --git a/en/src/functional-programing/iterator.md b/en/src/functional-programing/iterator.md
index 138ad19..0e774c6 100644
--- a/en/src/functional-programing/iterator.md
+++ b/en/src/functional-programing/iterator.md
@@ -305,7 +305,7 @@ fn main() {
 
 12. 🌟🌟 
 
-```rust
+```rust,editable
 /* Fill in the blanks */
 #[derive(PartialEq, Debug)]
 struct Shoe {