diff --git a/docs/docs/adding-an-rss-feed.md b/docs/docs/adding-an-rss-feed.md
index 053d9f500902e..8aa93c6e5a570 100644
--- a/docs/docs/adding-an-rss-feed.md
+++ b/docs/docs/adding-an-rss-feed.md
@@ -159,7 +159,8 @@ module.exports = {
           }
         `,
         /* highlight-start */
-        setup: () => ({
+        setup: options => ({
+          ...options,
           custom_namespaces: {
             itunes: 'http://www.itunes.com/dtds/podcast-1.0.dtd',
           },