diff --git a/.ipynb_checkpoints/not_so_obvious_python_stuff-checkpoint.ipynb b/.ipynb_checkpoints/not_so_obvious_python_stuff-checkpoint.ipynb
index 6fd17cf..eb92669 100644
--- a/.ipynb_checkpoints/not_so_obvious_python_stuff-checkpoint.ipynb
+++ b/.ipynb_checkpoints/not_so_obvious_python_stuff-checkpoint.ipynb
@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:ae2429a793f28d6caf410da8ce5690a243070d84b5eb141245c096e374c168d5"
+  "signature": "sha256:9b684ae1d67b480d34f80c15b281859c0bc91e94b26b941fa04ce142f3505c5d"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -1108,19 +1108,19 @@
      "input": [
       "def test_plainlist(plain_list):\n",
       "    for i in plain_list:\n",
-      "        print(i)\n",
+      "        pass\n",
       "\n",
       "def test_listcompr(listcompr):\n",
       "    for i in listcompr:\n",
-      "        print(i)\n",
+      "        pass\n",
       "\n",
       "def test_generator(generator):\n",
       "    for i in generator:\n",
-      "        print(i)\n",
+      "        pass\n",
       "\n",
       "def test_generator_yield(generator_yield):\n",
       "    for i in generator_yield:\n",
-      "        print(i)\n",
+      "        pass\n",
       "\n",
       "print('plain_list:     ', end = '')\n",
       "%timeit test_plainlist\n",
@@ -1138,7 +1138,7 @@
        "output_type": "stream",
        "stream": "stdout",
        "text": [
-        "plain_list:     10000000 loops, best of 3: 54.5 ns per loop"
+        "plain_list:     10000000 loops, best of 3: 55.6 ns per loop"
        ]
       },
       {
@@ -1147,7 +1147,7 @@
        "text": [
         "\n",
         "\n",
-        "listcompr:     10000000 loops, best of 3: 54.4 ns per loop"
+        "listcompr:     10000000 loops, best of 3: 54.8 ns per loop"
        ]
       },
       {
@@ -1165,7 +1165,7 @@
        "text": [
         "\n",
         "\n",
-        "generator_yield:     10000000 loops, best of 3: 52.4 ns per loop"
+        "generator_yield:     10000000 loops, best of 3: 54.7 ns per loop"
        ]
       },
       {
@@ -1176,7 +1176,7 @@
        ]
       }
      ],
-     "prompt_number": 1
+     "prompt_number": 2
     },
     {
      "cell_type": "code",
diff --git a/not_so_obvious_python_stuff.ipynb b/not_so_obvious_python_stuff.ipynb
index 6fd17cf..eb92669 100644
--- a/not_so_obvious_python_stuff.ipynb
+++ b/not_so_obvious_python_stuff.ipynb
@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:ae2429a793f28d6caf410da8ce5690a243070d84b5eb141245c096e374c168d5"
+  "signature": "sha256:9b684ae1d67b480d34f80c15b281859c0bc91e94b26b941fa04ce142f3505c5d"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -1108,19 +1108,19 @@
      "input": [
       "def test_plainlist(plain_list):\n",
       "    for i in plain_list:\n",
-      "        print(i)\n",
+      "        pass\n",
       "\n",
       "def test_listcompr(listcompr):\n",
       "    for i in listcompr:\n",
-      "        print(i)\n",
+      "        pass\n",
       "\n",
       "def test_generator(generator):\n",
       "    for i in generator:\n",
-      "        print(i)\n",
+      "        pass\n",
       "\n",
       "def test_generator_yield(generator_yield):\n",
       "    for i in generator_yield:\n",
-      "        print(i)\n",
+      "        pass\n",
       "\n",
       "print('plain_list:     ', end = '')\n",
       "%timeit test_plainlist\n",
@@ -1138,7 +1138,7 @@
        "output_type": "stream",
        "stream": "stdout",
        "text": [
-        "plain_list:     10000000 loops, best of 3: 54.5 ns per loop"
+        "plain_list:     10000000 loops, best of 3: 55.6 ns per loop"
        ]
       },
       {
@@ -1147,7 +1147,7 @@
        "text": [
         "\n",
         "\n",
-        "listcompr:     10000000 loops, best of 3: 54.4 ns per loop"
+        "listcompr:     10000000 loops, best of 3: 54.8 ns per loop"
        ]
       },
       {
@@ -1165,7 +1165,7 @@
        "text": [
         "\n",
         "\n",
-        "generator_yield:     10000000 loops, best of 3: 52.4 ns per loop"
+        "generator_yield:     10000000 loops, best of 3: 54.7 ns per loop"
        ]
       },
       {
@@ -1176,7 +1176,7 @@
        ]
       }
      ],
-     "prompt_number": 1
+     "prompt_number": 2
     },
     {
      "cell_type": "code",