Ensure python 2 support for chapters 13 and 14

13_convolutional_neural_networks.ipynb

@@ -455,7 +455,7 @@
    "source": [
     "import sys\n",
     "import tarfile\n",
-    "import urllib.request\n",
+    "from six.moves import urllib\n",
     "\n",
     "TF_MODELS_URL = \"http://download.tensorflow.org/models\"\n",
     "INCEPTION_V3_URL = TF_MODELS_URL + \"/inception_v3_2016_08_28.tar.gz\"\n",

14_recurrent_neural_networks.ipynb

@@ -1476,13 +1476,27 @@
    "source": [
     "from six.moves import urllib\n",
     "\n",
+    "import errno\n",
     "import os\n",
     "import zipfile\n",
-    "import urllib.request\n",
     "\n",
     "WORDS_PATH = \"datasets/words\"\n",
     "WORDS_URL = 'http://mattmahoney.net/dc/text8.zip'\n",
     "\n",
+    "def mkdir_p(path):\n",
+    "    \"\"\"Create directories, ok if they already exist.\n",
+    "    \n",
+    "    This is for python 2 support. In python >=3.2, simply use:\n",
+    "    >>> os.makedirs(path, exist_ok=True)\n",
+    "    \"\"\"\n",
+    "    try:\n",
+    "        os.makedirs(path)\n",
+    "    except OSError as exc:\n",
+    "        if exc.errno == errno.EEXIST and os.path.isdir(path):\n",
+    "            pass\n",
+    "        else:\n",
+    "            raise\n",
+    "\n",
     "def fetch_words_data(words_url=WORDS_URL, words_path=WORDS_PATH):\n",
     "    os.makedirs(words_path, exist_ok=True)\n",
     "    zip_path = os.path.join(words_path, \"words.zip\")\n",