diff --git a/pages/guides/collections.mdx b/pages/guides/collections.mdx
index 946a33e..06eb43f 100644
--- a/pages/guides/collections.mdx
+++ b/pages/guides/collections.mdx
@@ -444,7 +444,7 @@ collection User {
   }
 
   setUSD (val: number) {
-    this.codes["USD"] = val;
+    this.currency["USD"] = val;
   }
 }
 ```