Code toggling instructions. (#757)

python/ray/WebUI.ipynb

@@ -1,5 +1,28 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Ray UI.\n",
+    "\n",
+    "#### To run the UI: \n",
+    "1. Kernel -> Restart and Run All \n",
+    "\n",
+    "\n",
+    "#### To hide the code:\n",
+    "\n",
+    "1. Install the hide_code extension.\n",
+    "```\n",
+    "pip install hide_code\n",
+    "jupyter nbextension install --py hide_code\n",
+    "jupyter nbextension enable --py hide_code\n",
+    "jupyter serverextension enable --py hide_code\n",
+    "```\n",
+    "2. Go to View -> Cell Toolbar -> Hide Code. \n",
+    "3. Press ESC then T"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -11,6 +34,7 @@
     "import ipywidgets as widgets\n",
     "import numpy as np\n",
     "import os\n",
+    "import pprint\n",
     "import ray\n",
     "import subprocess\n",
     "import tempfile\n",