Merge pull request Esri#301 from Qberto/master

thanks @Qberto

Author: AtmaMani

talks/uc2018/IntegratingMLandDeepLearning/1_TensorFlow/3 - City Detection.ipynb

@@ -444,7 +444,8 @@
     "\n",
     "        for iteration in range(1000):\n",
     "            # TrafficLand API source JSON\n",
-    "            source_json = r\"http://api.trafficland.com/v1.5/json/video_feeds?system=ddot&key=1594c8892d7fbd18181a8a6a44958b28\"\n",
+    "            trafficland_API_key = os.environ['TRAFFICLAND_API_KEY']  # \n",
+    "            source_json = r\"http://api.trafficland.com/v1.5/json/video_feeds?system=ddot&key={0}\".format(trafficland_API_key)\n",
     "            df = pd.read_json(source_json)\n",
     "            ddot_df = df.loc[df.provider == 'DDOT']\n",
     "            \n",
@@ -1590,7 +1591,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.1"
+   "version": "3.6.6"
   }
  },
  "nbformat": 4,