diff --git a/nebraska/nebraska.py b/nebraska/nebraska.py
index c66c4d5..239335f 100755
--- a/nebraska/nebraska.py
+++ b/nebraska/nebraska.py
@@ -13,7 +13,6 @@
 import base64
 import copy
 import errno
-import httplib
 import json
 import logging
 import os
@@ -22,13 +21,15 @@
 import sys
 import threading
 import traceback
-import urlparse
 
 from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
 from datetime import datetime, time
 from xml.dom import minidom
 from xml.etree import ElementTree
 
+from six.moves import http_client
+from six.moves import urllib
+
 
 class NebraskaError(Exception):
   """The base class for failures raised by Nebraska."""
@@ -166,7 +167,7 @@
             'All apps should have "{}" attribute.'.format(attribute))
 
       # Filter out the None elements into a set.
-      unique_attrs = set(filter(None, all_attrs))
+      unique_attrs = set(x for x in all_attrs if x is not None)
       if len(unique_attrs) == 0:
         raise NebraskaErrorInvalidRequest('"{}" attribute should appear in at '
                                           'least one app.'.format(attribute))
@@ -367,7 +368,7 @@
     def __init__(self, app_request, properties):
       """Initialize an AppResponse.
 
-      Attributes:
+      Args:
         app_request: AppRequest representing a client request.
         properties: An instance of NebraskaProperties.
       """
@@ -476,15 +477,14 @@
   since we can have multiple payloads for a given app (delta/full payloads). The
   index is built by scanning a given directory for json files that describe the
   available payloads.
+
+  Attributes:
+    _directory: Directory containing metdata and payloads, can be None.
+    _index: A list of AppData describing payloads.
   """
 
   def __init__(self, directory):
-    """Initializes an AppIndex instance.
-
-    Attributes:
-      directory: Directory containing metdata and payloads, can be None.
-      index: A list of AppData describing payloads.
-    """
+    """Initializes an AppIndex instance."""
     self._directory = directory
     self._index = []
 
@@ -575,8 +575,20 @@
     Data about an available app that can be either installed or upgraded
     to. This information is compiled into XML format and returned to the client
     in an app tag in the server's response to an update or install request.
-    """
 
+    Attributes:
+      appid: appid of the requested app.
+      name: Filename of requested app on the mock Lorry server.
+      is_delta: True iff the payload is a delta update.
+      size: Size of the payload.
+      metadata_signature: Metadata signature.
+      metadata_size: Metadata size.
+      sha256_hex: SHA256 hash of the payload encoded in hexadecimal.
+      target_version: ChromeOS version the payload is tied to.
+      source_version: Source version for delta updates.
+      public_key: The public key for signature verification. It should be in
+                  base64 format.
+    """
     APPID_KEY = 'appid'
     NAME_KEY = 'name'
     IS_DELTA_KEY = 'is_delta'
@@ -594,20 +606,6 @@
       Args:
         app_data: Dictionary containing attributes used to initialize AppData
             instance.
-
-      Attributes:
-        template: Defines the format of an app element in the XML response.
-        appid: appid of the requested app.
-        name: Filename of requested app on the mock Lorry server.
-        is_delta: True iff the payload is a delta update.
-        size: Size of the payload.
-        metadata_signature: Metadata signature.
-        metadata_size: Metadata size.
-        sha256_hex: SHA256 hash of the payload encoded in hexadecimal.
-        target_version: ChromeOS version the payload is tied to.
-        source_version: Source version for delta updates.
-        public_key: The public key for signature verification. It should be in
-            base64 format.
       """
       self.appid = app_data[self.APPID_KEY]
       self.name = app_data[self.NAME_KEY]
@@ -728,6 +726,7 @@
     """Returns the request logs in JSON format."""
     return json.dumps(self._request_log)
 
+
 class NebraskaServer(object):
   """A simple Omaha server instance.
 
@@ -762,7 +761,7 @@
   class NebraskaHandler(BaseHTTPRequestHandler):
     """HTTP request handler for Omaha requests."""
 
-    def _SendResponse(self, content_type, response, code=httplib.OK):
+    def _SendResponse(self, content_type, response, code=http_client.OK):
       """Sends a given response back to the client.
 
       Args:
@@ -787,9 +786,9 @@
         - http://goo.gle/path/?key=value1&key=value2 ->
           ('path', {'key': ['value1', 'value2']})
       """
-      parsed_result = urlparse.urlparse(url)
+      parsed_result = urllib.parse.urlparse(url)
       parsed_path = parsed_result.path.strip('/')
-      parsed_query = urlparse.parse_qs(parsed_result.query)
+      parsed_query = urllib.parse.parse_qs(parsed_result.query)
       return parsed_path, parsed_query
 
     def do_POST(self):
@@ -807,7 +806,7 @@
         request_len = int(self.headers.getheader('content-length'))
         request = self.rfile.read(request_len)
       except Exception as err:
-        self.send_error(httplib.BAD_REQUEST, 'Invalid request (header).')
+        self.send_error(http_client.BAD_REQUEST, 'Invalid request (header).')
         return
 
       parsed_path, parsed_query = self._ParseURL(self.path)
@@ -824,11 +823,12 @@
         except Exception as err:
           logging.error('Failed to handle request (%s)', str(err))
           logging.error(traceback.format_exc())
-          self.send_error(httplib.INTERNAL_SERVER_ERROR, traceback.format_exc())
+          self.send_error(http_client.INTERNAL_SERVER_ERROR,
+                          traceback.format_exc())
 
       else:
         logging.error('The requested path "%s" was not found!', parsed_path)
-        self.send_error(httplib.BAD_REQUEST,
+        self.send_error(http_client.BAD_REQUEST,
                         'The requested path "%s" was not found!' % parsed_path)
 
     def do_GET(self):
@@ -849,10 +849,11 @@
         except Exception as err:
           logging.error('Failed to get request logs (%s)', str(err))
           logging.error(traceback.format_exc())
-          self.send_error(httplib.INTERNAL_SERVER_ERROR, traceback.format_exc())
+          self.send_error(http_client.INTERNAL_SERVER_ERROR,
+                          traceback.format_exc())
       else:
         logging.error('The requested path "%s" was not found!', parsed_path)
-        self.send_error(httplib.BAD_REQUEST,
+        self.send_error(http_client.BAD_REQUEST,
                         'The requested path "%s" was not found!' % parsed_path)
 
   def Start(self):
diff --git a/nebraska/nebraska_unittest.py b/nebraska/nebraska_unittest.py
index 14119ad..e167a62 100755
--- a/nebraska/nebraska_unittest.py
+++ b/nebraska/nebraska_unittest.py
@@ -9,7 +9,6 @@
 from __future__ import print_function
 
 # pylint: disable=cros-logging-import
-import httplib
 import logging
 import os
 import shutil
@@ -19,6 +18,8 @@
 from xml.etree import ElementTree
 import mock
 
+from six.moves import http_client
+
 import nebraska
 
 _NEBRASKA_PORT = 11235
@@ -189,7 +190,8 @@
     nebraska_handler.do_POST()
 
     nebraska_handler.send_error.assert_called_once_with(
-        httplib.BAD_REQUEST, 'The requested path "invalid-path" was not found!')
+        http_client.BAD_REQUEST,
+        'The requested path "invalid-path" was not found!')
 
   def testDoPostInvalidRequest(self):
     """Test do_POST invalid request."""
@@ -203,7 +205,7 @@
 
         self.assertEqual(traceback_mock.format_exc.call_count, 2)
         nebraska_handler.send_error.assert_called_once_with(
-            httplib.INTERNAL_SERVER_ERROR, traceback_mock.format_exc())
+            http_client.INTERNAL_SERVER_ERROR, traceback_mock.format_exc())
 
   def testDoPostInvalidResponse(self):
     """Tests do_POST invalid response handling."""
@@ -218,7 +220,7 @@
 
         self.assertEqual(traceback_mock.format_exc.call_count, 2)
         nebraska_handler.send_error.assert_called_once_with(
-            httplib.INTERNAL_SERVER_ERROR, traceback_mock.format_exc())
+            http_client.INTERNAL_SERVER_ERROR, traceback_mock.format_exc())
 
   def testDoGetSuccess(self):
     """Tests do_GET success."""
@@ -235,7 +237,7 @@
     nebraska_handler.path = 'http://test.com/invalid-path'
 
     nebraska_handler.do_GET()
-    nebraska_handler.send_error(httplib.BAD_REQUEST, mock.ANY)
+    nebraska_handler.send_error(http_client.BAD_REQUEST, mock.ANY)
 
 class NebraskaServerTest(NebraskaUnitTest):
   """Test NebraskaServer."""