diff --git a/docs/vnstock_ezchart_demo.ipynb b/docs/vnstock_ezchart_demo.ipynb
index 52ec326..664db3f 100644
--- a/docs/vnstock_ezchart_demo.ipynb
+++ b/docs/vnstock_ezchart_demo.ipynb
@@ -559,6 +559,13 @@
     "                 title_fontsize=14)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Heatmap"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": 43,