diff --git a/site/en/guide/intro_to_modules.ipynb b/site/en/guide/intro_to_modules.ipynb
index 1bedb87e894..79bbe89ca56 100644
--- a/site/en/guide/intro_to_modules.ipynb
+++ b/site/en/guide/intro_to_modules.ipynb
@@ -91,6 +91,7 @@
       "outputs": [],
       "source": [
         "import tensorflow as tf\n",
+        "import keras\n",
         "from datetime import datetime\n",
         "\n",
         "%load_ext tensorboard"
@@ -918,6 +919,7 @@
       },
       "outputs": [],
       "source": [
+        "@keras.saving.register_keras_serializable()\n",
         "class MySequentialModel(tf.keras.Model):\n",
         "  def __init__(self, name=None, **kwargs):\n",
         "    super().__init__(**kwargs)\n",