fix import alpha order

Author: JohnLZeller

tests/test_api_object.py

@@ -6,10 +6,10 @@
 
 import copy
 import json
+from requests.models import Response
 import six
 import unittest2
 import warnings
-from requests.models import Response
 
 from coinbase.wallet.model import APIObject
 from coinbase.wallet.model import new_api_object