diff --git a/notebooks/08_Introduction_to_TensorFlow.ipynb b/notebooks/08_Introduction_to_TensorFlow.ipynb
index 5f77a4f..df21000 100644
--- a/notebooks/08_Introduction_to_TensorFlow.ipynb
+++ b/notebooks/08_Introduction_to_TensorFlow.ipynb
@@ -63,7 +63,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -89,7 +89,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": null,
    "metadata": {
     "collapsed": true
    },
@@ -110,7 +110,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": null,
    "metadata": {
     "collapsed": true
    },
@@ -129,7 +129,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": null,
    "metadata": {
     "collapsed": true
    },
@@ -151,7 +151,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": null,
    "metadata": {
     "collapsed": true
    },
@@ -170,7 +170,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": null,
    "metadata": {
     "collapsed": true
    },
@@ -193,7 +193,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": null,
    "metadata": {
     "collapsed": true
    },
@@ -219,7 +219,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 8,
+   "execution_count": null,
    "metadata": {
     "collapsed": true
    },
@@ -241,7 +241,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": null,
    "metadata": {
     "collapsed": true
    },
@@ -260,7 +260,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 10,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -286,23 +286,11 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 11,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "End of epoch 1: running error average = 0.39\n",
-      "End of epoch 2: running error average = 0.31\n",
-      "End of epoch 3: running error average = 0.30\n",
-      "End of epoch 4: running error average = 0.29\n",
-      "End of epoch 5: running error average = 0.29\n"
-     ]
-    }
-   ],
+   "outputs": [],
    "source": [
     "num_epoch = 5\n",
     "for e in range(num_epoch):\n",
@@ -325,7 +313,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 12,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -342,14 +330,7 @@
     "        across all batches in dataset and second value corresponding to\n",
     "        average classification accuracy across all batches in dataset.\n",
     "    \"\"\"\n",
-    "    err = 0\n",
-    "    acc = 0\n",
-    "    for input_batch, target_batch in data:\n",
-    "        err += sess.run(error, feed_dict={inputs: input_batch, targets: target_batch})\n",
-    "        acc += sess.run(accuracy, feed_dict={inputs: input_batch, targets: target_batch})\n",
-    "    err /= data.num_batches\n",
-    "    acc /= data.num_batches\n",
-    "    return err, acc"
+    "    raise NotImplementedError()"
    ]
   },
   {
@@ -361,20 +342,11 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 13,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "Train data: Error=0.28 Accuracy=0.92\n",
-      "Valid data: Error=0.28 Accuracy=0.92\n"
-     ]
-    }
-   ],
+   "outputs": [],
    "source": [
     "print('Train data: Error={0:.2f} Accuracy={1:.2f}'\n",
     "      .format(*get_error_and_accuracy(train_data)))\n",
@@ -397,19 +369,11 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 14,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "Number of operations in graph: 99\n"
-     ]
-    }
-   ],
+   "outputs": [],
    "source": [
     "default_graph = tf.get_default_graph()\n",
     "print('Number of operations in graph: {0}'\n",
@@ -425,7 +389,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 15,
+   "execution_count": null,
    "metadata": {
     "collapsed": true
    },
@@ -449,7 +413,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 16,
+   "execution_count": null,
    "metadata": {
     "collapsed": true
    },