diff --git a/04-interface-and-class/interface-basics.md b/04-interface-and-class/interface-basics.md
index 24d657f..3539796 100644
--- a/04-interface-and-class/interface-basics.md
+++ b/04-interface-and-class/interface-basics.md
@@ -40,7 +40,7 @@ interface GetUserName {
   (user: User): string;
 }
 const getUserName: GetUserName = function (user) {
-  return user.name;
+  return user.data.name;
 };
 ```