diff --git a/client.py b/client.py
index 6fce288..a9068f3 100644
--- a/client.py
+++ b/client.py
@@ -2,34 +2,31 @@
 
 
 class DiffbotClient(object):
-    def __init__(self):
-        self.base_url = "http://api.diffbot.com/"
 
-    def request(self, url, token, api, fields=[], version=2, **kwargs):
+    base_url = 'http://api.diffbot.com/'
+
+    def request(self, url, token, api, fields=None, version=2, **kwargs):
         """
         Returns a python object containing the requested resource from the diffbot api
         """
         params = {"url": url, "token": token}
         if fields:
             params['fields'] = fields
-        if kwargs:
-            params.update(kwargs)
+        params.update(kwargs)
         response = requests.get(self.compose_url(api, version), params=params)
-        obj = response.json()
-        return obj
+        response.raise_for_status()
+        return response.json()
 
     def compose_url(self, api, version_number):
         """
         Returns the uri for an endpoint as a string
         """
         version = self.format_version_string(version_number)
-        url = self.base_url + version + "/" + api
-        return url
+        return '{}{}/{}'.format(self.base_url, version, api)
 
     @staticmethod
     def format_version_string(version_number):
         """
         Returns a string representation of the API version
         """
-        version = "v" + str(version_number)
-        return version
+        return 'v{}'.format(version_number)
diff --git a/requirements.txt b/requirements.txt
index 4713d5f..815c51c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1 @@
 requests==2.1.0
-
diff --git a/tests/unit_test.py b/tests/unit_test.py
index a8d2c3e..fe510a0 100644
--- a/tests/unit_test.py
+++ b/tests/unit_test.py
@@ -1,17 +1,12 @@
 import os
 import urlparse
 import unittest
-import simplejson
-import logging
 import requests
-from mock import Mock, patch
+from mock import patch
 
 from client import DiffbotClient
 
 
-logger = logging.getLogger(__name__)
-
-
 def fake_get(url, params):
     path = urlparse.urlparse(url).path
     path_tuple = os.path.split(path)
@@ -82,4 +77,4 @@ def test_analyze_api(self):
 
 
 if __name__ == '__main__':
-    unittest.main()
\ No newline at end of file
+    unittest.main()