update notebook

Author: Dou Du

example/example.ipynb

@@ -2,19 +2,9 @@
  "cells": [
   {
    "cell_type": "code",
-   "execution_count": 13,
+   "execution_count": null,
    "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "The autoreload extension is already loaded. To reload it, use:\n",
-      "  %reload_ext autoreload\n",
-      "env: ANYWIDGET_HMR=1\n"
-     ]
-    }
-   ],
+   "outputs": [],
    "source": [
     "# This cell (autoloading & hot module replacement) is only needed for development!\n",
     "%load_ext autoreload\n",
@@ -24,24 +14,9 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 14,
+   "execution_count": null,
    "metadata": {},
-   "outputs": [
-    {
-     "data": {
-      "application/vnd.jupyter.widget-view+json": {
-       "model_id": "067c689334a14910a7f11d529b60f922",
-       "version_major": 2,
-       "version_minor": 1
-      },
-      "text/plain": [
-       "BZVisualizer(disable_interact_overlay=True, height='800px', seekpath_data={'faces_data': {'triangles_vertices'…"
-      ]
-     },
-     "metadata": {},
-     "output_type": "display_data"
-    }
-   ],
+   "outputs": [],
    "source": [
     "from widget_bzvisualizer import BZVisualizer\n",
     "\n",
@@ -68,7 +43,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 15,
+   "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -82,24 +57,9 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 17,
+   "execution_count": null,
    "metadata": {},
-   "outputs": [
-    {
-     "data": {
-      "application/vnd.jupyter.widget-view+json": {
-       "model_id": "2acda8bf7ef946388c889d763521417b",
-       "version_major": 2,
-       "version_minor": 1
-      },
-      "text/plain": [
-       "BZVisualizer(height='800px', seekpath_data={'faces_data': {'triangles_vertices': [[-1.1089190599406602, -2.220…"
-      ]
-     },
-     "metadata": {},
-     "output_type": "display_data"
-    }
-   ],
+   "outputs": [],
    "source": [
     "# Load info with ASE\n",
     "# NOTE: (ASE is not included as a direct dependency, needs to be installed separately)\n",
@@ -115,13 +75,6 @@
     "display(bz2)"
    ]
   },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
   {
    "cell_type": "code",
    "execution_count": null,