#763 update error handing documentation

TROUBLESHOOTING.md

@@ -32,25 +32,28 @@ In the first case, SENDGRID_API_KEY is in reference to the name of the environme
 <a name="error"></a>
 ## Error Messages
 
-To read the error message returned by Twilio SendGrid's API in Python 2.X:
+HTTP exceptions are defined in the [`python_http_client` package](https://github.com/sendgrid/python-http-client/blob/master/python_http_client/exceptions.py).
+
+To read the error message returned by SendGrid's API in Python 2.X:
 
 ```python
-import urllib2
+from python_http_client.exceptions import HTTPError
 
 try:
-  response = sendgrid_client.send(request_body=mail.get())
-except urllib2.HTTPError as e:
-    print(e.read())
+  response = sg.client.mail.send.post(request_body=mail.get())
+except HTTPError as e:
+    print e.to_dict
 ```
 
 To read the error message returned by Twilio SendGrid's API in Python 3.X:
 
 ```python
-import urllib
+from python_http_client.exceptions import HTTPError
+
 try:
-  response = sendgrid_client.send(request_body=mail.get())
-except urllib.error.HTTPError as e:
-    print(e.read())
+  response = sg.client.mail.send.post(request_body=mail.get())
+except HTTPError as e:
+    print(e.to_dict)
 ```
 
 <a name="migrating"></a>