diff --git a/docs/guides/cloning-medium-with-parchment.md b/docs/guides/cloning-medium-with-parchment.md
index 0e0a0f523d..8e8e2818f1 100644
--- a/docs/guides/cloning-medium-with-parchment.md
+++ b/docs/guides/cloning-medium-with-parchment.md
@@ -210,7 +210,7 @@ Additionally we will add support for widths and heights, as unregistered formats
 class VideoBlot extends BlockEmbed {
   static create(url) {
     let node = super.create();
-
+    node.setAttribute('src', url);
     // Set non-format related attributes with static values
     node.setAttribute('frameborder', '0');
     node.setAttribute('allowfullscreen', true);