diff --git a/avs/alexa.py b/avs/alexa.py
index 60edc53..bbeb002 100755
--- a/avs/alexa.py
+++ b/avs/alexa.py
@@ -1,17 +1,16 @@
 # -*- coding: utf-8 -*-
 
 
+import base64
 import cgi
-import io
 import json
 import logging
 import os
+import signal
 import sys
 import tempfile
-import uuid
-import base64
-import signal
 import threading
+import uuid
 
 if sys.version_info < (3, 0):
     import Queue as queue
@@ -261,7 +260,7 @@ def _parse_response(self, response, boundary, buffer=''):
             # skip small data block
             if pos > blen:
                 # a blank line is between parts
-                parts = response[:pos-2].split('\r\n\r\n', 1)
+                parts = response[:pos - 2].split('\r\n\r\n', 1)
                 if parts[0].find('application/json') >= 0:
                     metadata = json.loads(parts[1].decode('utf-8'))
                     if 'directive' in metadata:
@@ -277,7 +276,7 @@ def _parse_response(self, response, boundary, buffer=''):
                             logger.info('write audio to {}.mp3'.format(filename))
                             break
 
-            response = response[pos+blen+2:]
+            response = response[pos + blen + 2:]
 
         for directive in directives:
             self._handle_directive(directive)
@@ -396,7 +395,7 @@ def main():
 
     is_quit = threading.Event()
 
-    def signal_handler(signal, frame):
+    def signal_handler(sig, frame):
         print('Quit')
         is_quit.set()
 
diff --git a/avs/auth.py b/avs/auth.py
index 1d9f7a5..439dfba 100644
--- a/avs/auth.py
+++ b/avs/auth.py
@@ -1,13 +1,13 @@
+import datetime
+import json
+import time
+import uuid
 
+import click
+import requests
 import tornado.httpserver
 import tornado.ioloop
 import tornado.web
-import time
-import json
-import uuid
-import requests
-import datetime
-import click
 
 import avs.config
 
@@ -116,4 +116,3 @@ def main(config, output):
 
 if __name__ == '__main__':
     main()
-
diff --git a/avs/check.py b/avs/check.py
index d413bb0..0a3405d 100644
--- a/avs/check.py
+++ b/avs/check.py
@@ -6,10 +6,11 @@
 It depends on respeaker python library (https://github.com/respeaker/respeaker_python_library)
 """
 
-import signal
 import audioop
 import os
+import signal
 import time
+
 from avs.mic import Audio
 from avs.player import Player
 
@@ -37,6 +38,7 @@ def main():
     player2 = Player()
 
     is_quit = []
+
     def signal_handler(signal, frame):
         print('Quit')
         is_quit.append(True)
@@ -51,7 +53,6 @@ def signal_handler(signal, frame):
         time.sleep(3)
         player2.pause()
 
-
     audio.stop()
 
 
diff --git a/avs/interface/alerts.py b/avs/interface/alerts.py
index 3e995e6..3a500d3 100644
--- a/avs/interface/alerts.py
+++ b/avs/interface/alerts.py
@@ -2,12 +2,13 @@
 
 """https://developer.amazon.com/public/solutions/alexa/alexa-voice-service/reference/alerts"""
 
+import datetime
 import os
 import time
-import datetime
-import dateutil.parser
-from threading import Timer, Event
 import uuid
+from threading import Timer, Event
+
+import dateutil.parser
 
 # prefer mpg123 player as it is more responsive than mpv and gstreamer
 if os.system('which mpg123 >/dev/null') == 0:
diff --git a/avs/interface/audio_player.py b/avs/interface/audio_player.py
index 6f5bdbe..87c8c5b 100644
--- a/avs/interface/audio_player.py
+++ b/avs/interface/audio_player.py
@@ -2,21 +2,21 @@
 
 """https://developer.amazon.com/public/solutions/alexa/alexa-voice-service/reference/audioplayer"""
 
-import os
-import time
-import tempfile
-import uuid
 import base64
 import hashlib
-import requests
 import logging
+import os
+import tempfile
+import uuid
 from contextlib import closing
+
+import requests
+
 try:
     from urllib.parse import urlparse
 except ImportError:
     from urlparse import urlparse
 
-
 from avs.player import Player
 
 logger = logging.getLogger('AudioPlayer')
diff --git a/avs/interface/speech_recognizer.py b/avs/interface/speech_recognizer.py
index 5c948bf..b42b3f7 100644
--- a/avs/interface/speech_recognizer.py
+++ b/avs/interface/speech_recognizer.py
@@ -4,8 +4,8 @@
 
 import logging
 import sys
-import time
 import threading
+import time
 import uuid
 
 if sys.version_info < (3, 0):
diff --git a/avs/interface/speech_synthesizer.py b/avs/interface/speech_synthesizer.py
index e9e8827..a8e5090 100644
--- a/avs/interface/speech_synthesizer.py
+++ b/avs/interface/speech_synthesizer.py
@@ -1,9 +1,9 @@
+import base64
+import logging
 import os
 import tempfile
 import threading
 import uuid
-import base64
-import logging
 
 # prefer mpg123 player as it is more responsive than mpv and gstreamer
 if os.system('which mpg123 >/dev/null') == 0:
diff --git a/avs/interface/system.py b/avs/interface/system.py
index 18cbf6b..e274a3a 100755
--- a/avs/interface/system.py
+++ b/avs/interface/system.py
@@ -1,8 +1,7 @@
-
 """https://developer.amazon.com/public/solutions/alexa/alexa-voice-service/reference/system"""
 
-import uuid
 import datetime
+import uuid
 
 
 class System(object):
diff --git a/avs/main.py b/avs/main.py
index 8920900..a19585f 100644
--- a/avs/main.py
+++ b/avs/main.py
@@ -6,12 +6,11 @@
 It depends on respeaker python library (https://github.com/respeaker/respeaker_python_library)
 """
 
-
-import sys
+import logging
 import signal
-import time
+import sys
 import threading
-import logging
+import time
 
 if sys.version_info < (3, 0):
     import Queue as queue
@@ -22,10 +21,10 @@
 from avs.mic import Audio
 from respeaker.pixel_ring import pixel_ring
 
-
 logger = logging.getLogger(__file__)
 logging.basicConfig(level=logging.INFO)
 
+
 class KWS(object):
     def __init__(self):
         self.queue = queue.Queue()
@@ -112,7 +111,7 @@ def wakeup(keyword):
     audio.start()
 
     is_quit = threading.Event()
-    
+
     def signal_handler(signal, frame):
         print('Quit')
         is_quit.set()
diff --git a/avs/mic/__init__.py b/avs/mic/__init__.py
index eef842d..9de57ac 100644
--- a/avs/mic/__init__.py
+++ b/avs/mic/__init__.py
@@ -2,7 +2,6 @@
 
 import os
 
-
 recorder_option = os.getenv('RECORDER', 'default').lower()
 
 if recorder_option.find('pyaudio') >= 0 or os.system('which arecord >/dev/null') != 0:
@@ -10,5 +9,4 @@
 else:
     from alsa_recorder import Audio
 
-
 __all__ = ['Audio']
diff --git a/avs/mic/alsa_recorder.py b/avs/mic/alsa_recorder.py
index 0c3765f..b0eeaa3 100755
--- a/avs/mic/alsa_recorder.py
+++ b/avs/mic/alsa_recorder.py
@@ -1,12 +1,10 @@
 # -*- coding: utf-8 -*-
 
-import os
 import subprocess
 import threading
 
 
 class Audio(object):
-
     def __init__(self, rate=16000, frames_size=160, channels=1, device_name='default'):
         self.rate = rate
         self.frames_size = frames_size
diff --git a/avs/mic/pyaudio_recorder.py b/avs/mic/pyaudio_recorder.py
index 090bcb3..966de09 100755
--- a/avs/mic/pyaudio_recorder.py
+++ b/avs/mic/pyaudio_recorder.py
@@ -1,14 +1,13 @@
 # -*- coding: utf-8 -*-
 
 
-import pyaudio
 import logging
+import pyaudio
 
 logger = logging.getLogger(__file__)
 
 
 class Audio(object):
-
     def __init__(self, rate=16000, frames_size=None, channels=None, device_index=None):
         self.sample_rate = rate
         self.frames_size = frames_size if frames_size else rate / 100
@@ -64,5 +63,3 @@ def link(self, sink):
 
     def unlink(self, sink):
         self.sinks.remove(sink)
-
-
diff --git a/avs/player/__init__.py b/avs/player/__init__.py
index 35f3444..9d76f07 100644
--- a/avs/player/__init__.py
+++ b/avs/player/__init__.py
@@ -27,6 +27,4 @@
         else:
             raise ImportError('No player available, install one of the players: gstreamer, mpv and mpg123 first')
 
-
 __all__ = ['Player']
-
diff --git a/avs/player/gstreamer_player.py b/avs/player/gstreamer_player.py
index 0fde5af..8e7cc15 100644
--- a/avs/player/gstreamer_player.py
+++ b/avs/player/gstreamer_player.py
@@ -2,10 +2,10 @@
 
 """Player using gstreamer."""
 
-import time
+import gi
 import threading
+import time
 
-import gi
 gi.require_version('Gst', '1.0')
 from gi.repository import Gst, GLib, GObject
 
@@ -68,8 +68,8 @@ def on_message(self, bus, message):
             self.player.set_state(Gst.State.NULL)
             if 'error' in self.callbacks:
                 self.callbacks['error']()
-        # else:
-        #     print(message.type)
+                # else:
+                #     print(message.type)
 
     @property
     def duration(self):
@@ -101,4 +101,3 @@ def state(self):
         # GST_STATE_PLAYING             the element is PLAYING, the GstClock is running and the data is flowing.
         _, state, _ = self.player.get_state(Gst.SECOND)
         return 'FINISHED' if state != Gst.State.PLAYING else 'PLAYING'
-
diff --git a/avs/player/mpg123_player.py b/avs/player/mpg123_player.py
index 2566f3f..0974190 100644
--- a/avs/player/mpg123_player.py
+++ b/avs/player/mpg123_player.py
@@ -3,13 +3,13 @@
 """Player using mpg123"""
 
 import os
-import signal
-import threading
 import subprocess
+import threading
 
 if os.system('which mpg123 >/dev/null') != 0:
     ImportError('mpg123 not found, install it first')
 
+
 class Player(object):
     def __init__(self):
         self.callbacks = {}
@@ -30,7 +30,7 @@ def _run(self):
             print('Playing {}'.format(self.audio))
 
             master, slave = os.openpty()
-            self.process = subprocess.Popen(['mpg123','-q', '-C', self.audio], stdin=master)
+            self.process = subprocess.Popen(['mpg123', '-q', '-C', self.audio], stdin=master)
             self.tty = slave
 
             self.process.wait()
@@ -48,9 +48,9 @@ def play(self, uri):
 
         if self.process and self.process.poll() == None:
             os.write(self.tty, 'q')
-            
+
         self.state = 'PLAYING'
-        
+
     def stop(self):
         if self.process and self.process.poll() == None:
             os.write(self.tty, 'q')
diff --git a/avs/player/mpv_player.py b/avs/player/mpv_player.py
index 358e602..60f5d95 100644
--- a/avs/player/mpv_player.py
+++ b/avs/player/mpv_player.py
@@ -3,9 +3,8 @@
 """Player using MPV"""
 
 import os
-import signal
-import threading
 import subprocess
+import threading
 
 if os.system('which mpv >/dev/null') != 0:
     raise ImportError('mpv not found, install it first')
@@ -46,9 +45,9 @@ def play(self, uri):
 
         if self.process and self.process.poll() == None:
             os.write(self.tty, 'q')
-            
+
         self.state = 'PLAYING'
-        
+
     def stop(self):
         if self.process and self.process.poll() == None:
             os.write(self.tty, 'q')