diff --git a/mopidy/backends/base/playback.py b/mopidy/backends/base/playback.py
index 51fe0d3b..16ac75d1 100644
--- a/mopidy/backends/base/playback.py
+++ b/mopidy/backends/base/playback.py
@@ -2,8 +2,6 @@ import logging
 import random
 import time
 
-from pykka.registry import ActorRegistry
-
 from mopidy.listeners import BackendListener
 
 logger = logging.getLogger('mopidy.backends.base')
diff --git a/mopidy/backends/spotify/__init__.py b/mopidy/backends/spotify/__init__.py
index ad45014e..56775926 100644
--- a/mopidy/backends/spotify/__init__.py
+++ b/mopidy/backends/spotify/__init__.py
@@ -10,7 +10,6 @@ from mopidy.gstreamer import GStreamer
 
 logger = logging.getLogger('mopidy.backends.spotify')
 
-ENCODING = 'utf-8'
 BITRATES = {96: 2, 160: 0, 320: 1}
 
 class SpotifyBackend(ThreadingActor, Backend):
diff --git a/mopidy/backends/spotify/library.py b/mopidy/backends/spotify/library.py
index 59aa9a2c..a080c7bd 100644
--- a/mopidy/backends/spotify/library.py
+++ b/mopidy/backends/spotify/library.py
@@ -4,7 +4,6 @@ import Queue
 from spotify import Link, SpotifyError
 
 from mopidy.backends.base import BaseLibraryProvider
-from mopidy.backends.spotify import ENCODING
 from mopidy.backends.spotify.translator import SpotifyTranslator
 from mopidy.models import Playlist
 
diff --git a/mopidy/backends/spotify/session_manager.py b/mopidy/backends/spotify/session_manager.py
index 4b81db1f..af731e1b 100644
--- a/mopidy/backends/spotify/session_manager.py
+++ b/mopidy/backends/spotify/session_manager.py
@@ -1,4 +1,3 @@
-import glib
 import logging
 import os
 import threading
diff --git a/mopidy/backends/spotify/translator.py b/mopidy/backends/spotify/translator.py
index 27f4719b..2f47a42b 100644
--- a/mopidy/backends/spotify/translator.py
+++ b/mopidy/backends/spotify/translator.py
@@ -4,7 +4,6 @@ import logging
 from spotify import Link, SpotifyError
 
 from mopidy import settings
-from mopidy.backends.spotify import ENCODING
 from mopidy.models import Artist, Album, Track, Playlist
 
 logger = logging.getLogger('mopidy.backends.spotify.translator')
diff --git a/mopidy/core.py b/mopidy/core.py
index 08c5e0d7..596e0fe5 100644
--- a/mopidy/core.py
+++ b/mopidy/core.py
@@ -12,14 +12,12 @@ gobject.threads_init()
 # so that GStreamer doesn't hijack e.g. ``--help``.
 # NOTE This naive fix does not support values like ``bar`` in
 # ``--gst-foo bar``. Use equals to pass values, like ``--gst-foo=bar``.
-def is_gst_arg(arg):
-    return arg.startswith('--gst') or arg == '--help-gst'
+def is_gst_arg(argument):
+    return argument.startswith('--gst') or argument == '--help-gst'
 gstreamer_args = [arg for arg in sys.argv[1:] if is_gst_arg(arg)]
 mopidy_args = [arg for arg in sys.argv[1:] if not is_gst_arg(arg)]
 sys.argv[1:] = gstreamer_args
 
-from pykka.registry import ActorRegistry
-
 from mopidy import (get_version, settings, OptionalDependencyError,
     SettingsError, DATA_PATH, SETTINGS_PATH, SETTINGS_FILE)
 from mopidy.gstreamer import GStreamer
diff --git a/mopidy/frontends/mpd/dispatcher.py b/mopidy/frontends/mpd/dispatcher.py
index 5ee70a5b..2b012c7c 100644
--- a/mopidy/frontends/mpd/dispatcher.py
+++ b/mopidy/frontends/mpd/dispatcher.py
@@ -244,7 +244,8 @@ class MpdContext(object):
         """
         if self._backend is None:
             backend_refs = ActorRegistry.get_by_class(Backend)
-            assert len(backend_refs) == 1, 'Expected exactly one running backend.'
+            assert len(backend_refs) == 1, \
+                'Expected exactly one running backend.'
             self._backend = backend_refs[0].proxy()
         return self._backend
 
diff --git a/mopidy/frontends/mpris/objects.py b/mopidy/frontends/mpris/objects.py
index e0a83e03..9ed1fe2c 100644
--- a/mopidy/frontends/mpris/objects.py
+++ b/mopidy/frontends/mpris/objects.py
@@ -81,7 +81,8 @@ class MprisObject(dbus.service.Object):
     def _connect_to_dbus(self):
         logger.debug(u'Connecting to D-Bus...')
         mainloop = dbus.mainloop.glib.DBusGMainLoop()
-        bus_name = dbus.service.BusName(BUS_NAME, dbus.SessionBus(mainloop=mainloop))
+        bus_name = dbus.service.BusName(BUS_NAME,
+            dbus.SessionBus(mainloop=mainloop))
         logger.info(u'Connected to D-Bus')
         return bus_name
 
diff --git a/mopidy/gstreamer.py b/mopidy/gstreamer.py
index ffb8c4f1..b6a8ab2b 100644
--- a/mopidy/gstreamer.py
+++ b/mopidy/gstreamer.py
@@ -332,7 +332,8 @@ class GStreamer(ThreadingActor):
         self._tee.send_event(event)
 
     def _handle_event_probe(self, teesrc, event):
-        if event.type == gst.EVENT_CUSTOM_DOWNSTREAM and event.has_name('mopidy-unlink-tee'):
+        if (event.type == gst.EVENT_CUSTOM_DOWNSTREAM
+                and event.has_name('mopidy-unlink-tee')):
             data = self._get_structure_data(event.get_structure())
 
             output = teesrc.get_peer().get_parent()
diff --git a/mopidy/utils/settings.py b/mopidy/utils/settings.py
index fca4f337..ff449a61 100644
--- a/mopidy/utils/settings.py
+++ b/mopidy/utils/settings.py
@@ -2,7 +2,6 @@
 from __future__ import absolute_import
 from copy import copy
 import getpass
-import glib
 import logging
 import os
 from pprint import pformat