diff --git a/index.ipynb b/index.ipynb
index f6c1531b9c..07ea3dfce4 100644
--- a/index.ipynb
+++ b/index.ipynb
@@ -65,9 +65,7 @@
    "execution_count": null,
    "metadata": {},
    "outputs": [],
-   "source": [
-    "z"
-   ]
+   "source": []
   },
   {
    "cell_type": "markdown",