diff --git a/docs/developer-guide/custom-layers/subclassed-layers.md b/docs/developer-guide/custom-layers/subclassed-layers.md
index 754354c3606..c5c142f8f87 100644
--- a/docs/developer-guide/custom-layers/subclassed-layers.md
+++ b/docs/developer-guide/custom-layers/subclassed-layers.md
@@ -12,13 +12,21 @@ good technique to add it.
 ```js
 // Example to add per-segment color to PathLayer
 import {PathLayer} from '@deck.gl/layers';
+import GL from '@luma.gl/constants';
 
 // Allow accessor: `getColor` (Function, optional)
 // Returns an color (array of numbers, RGBA) or array of colors (array of arrays).
 export default class MultiColorPathLayer extends PathLayer {
   initializeState() {
     super.initializeState();
-    this.getAttributeManager().getAttributes().instanceColors.update = this.calculateColors;
+    this.getAttributeManager().addInstanced({
+      instanceColors: {
+        size: 4,
+        type: GL.UNSIGNED_BYTE,
+        normalized: true,
+        update: this.calculateColors
+      }
+    })
   }
 
   calculateColors(attribute) {