Added comment.

module3/exo1/influenza-like-illness-analysis.ipynb

@@ -35,6 +35,27 @@
     "data_url = \"http://www.sentiweb.fr/datasets/incidence-PAY-3.csv\""
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "To ensure that we always have an available copy of the data, we will dowload it and keep a local version. If we already have a local version we wont download the data again."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "data_file = \"syndrome-grippal.csv\"\n",
+    "\n",
+    "import os\n",
+    "import urllib.request\n",
+    "if not os.path.exists(data_file):\n",
+    "    urllib.request.urlretrieve(data_url, data_file)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -57,20 +78,6 @@
     "The first line of the CSV file is a comment, which we ignore with `skip=1`."
    ]
   },
-  {
-   "cell_type": "code",
-   "execution_count": 18,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "data_file = \"syndrome-grippal.csv\"\n",
-    "\n",
-    "import os\n",
-    "import urllib.request\n",
-    "if not os.path.exists(data_file):\n",
-    "    urllib.request.urlretrieve(data_url, data_file)"
-   ]
-  },
   {
    "cell_type": "code",
    "execution_count": 19,