diff --git a/bin/wsdump.py b/bin/wsdump.py
index 0478070..5af00ac 100755
--- a/bin/wsdump.py
+++ b/bin/wsdump.py
@@ -2,12 +2,15 @@
 
 import argparse
 import code
-import six
 import sys
 import threading
 import time
-import websocket
+
+import six
 from six.moves.urllib.parse import urlparse
+
+import websocket
+
 try:
     import readline
 except ImportError:
diff --git a/compliance/test_fuzzingclient.py b/compliance/test_fuzzingclient.py
index 58c5ea6..f4b0ff1 100644
--- a/compliance/test_fuzzingclient.py
+++ b/compliance/test_fuzzingclient.py
@@ -1,13 +1,9 @@
 #!/usr/bin/env python
 
-import websocket
 import json
 import traceback
-import six
-
-
-
 
+import websocket
 
 SERVER = 'ws://127.0.0.1:8642'
 AGENT = 'py-websockets-client'
diff --git a/websocket/__init__.py b/websocket/__init__.py
index a895023..9b2cef5 100644
--- a/websocket/__init__.py
+++ b/websocket/__init__.py
@@ -19,7 +19,10 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
     Boston, MA  02110-1335  USA
 
 """
-from ._core import *
 from ._app import WebSocketApp
+from ._core import *
+from ._exceptions import *
+from ._logging import *
+from ._socket import *
 
 __version__ = "0.37.0"
diff --git a/websocket/_abnf.py b/websocket/_abnf.py
index 87503ce..fca07e6 100644
--- a/websocket/_abnf.py
+++ b/websocket/_abnf.py
@@ -19,10 +19,12 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
     Boston, MA  02110-1335  USA
 
 """
-import six
 import array
-import struct
 import os
+import struct
+
+import six
+
 from ._exceptions import *
 from ._utils import validate_utf8
 
@@ -44,6 +46,22 @@ except ImportError:
         else:
             return _d.tostring()
 
+__all__ = [
+    'ABNF', 'continuous_frame', 'frame_buffer',
+    'STATUS_NORMAL',
+    'STATUS_GOING_AWAY',
+    'STATUS_PROTOCOL_ERROR',
+    'STATUS_UNSUPPORTED_DATA_TYPE',
+    'STATUS_STATUS_NOT_AVAILABLE',
+    'STATUS_ABNORMAL_CLOSED',
+    'STATUS_INVALID_PAYLOAD',
+    'STATUS_POLICY_VIOLATION',
+    'STATUS_MESSAGE_TOO_BIG',
+    'STATUS_INVALID_EXTENSION',
+    'STATUS_UNEXPECTED_CONDITION',
+    'STATUS_TLS_HANDSHAKE_ERROR',
+]
+
 # closing frame status codes.
 STATUS_NORMAL = 1000
 STATUS_GOING_AWAY = 1001
diff --git a/websocket/_app.py b/websocket/_app.py
index 5096aef..3ea942d 100644
--- a/websocket/_app.py
+++ b/websocket/_app.py
@@ -23,17 +23,18 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
 """
 WebSocketApp provides higher level APIs.
 """
+import select
+import sys
 import threading
 import time
 import traceback
-import sys
-import select
+
 import six
 
+from ._abnf import ABNF
 from ._core import WebSocket, getdefaulttimeout
 from ._exceptions import *
 from ._logging import *
-from ._abnf import ABNF
 
 __all__ = ["WebSocketApp"]
 
diff --git a/websocket/_core.py b/websocket/_core.py
index e0be9f2..adcdb6b 100644
--- a/websocket/_core.py
+++ b/websocket/_core.py
@@ -21,24 +21,22 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
 """
 from __future__ import print_function
 
+import socket
+import struct
+import threading
 
 import six
-import socket
-
-if six.PY3:
-    from base64 import encodebytes as base64encode
-else:
-    from base64 import encodestring as base64encode
-
-import threading
 
 # websocket modules
 from ._abnf import *
+from ._exceptions import *
+from ._handshake import *
+from ._http import *
+from ._logging import *
 from ._socket import *
 from ._utils import *
-from ._logging import *
-from ._http import *
-from ._handshake import *
+
+__all__ = ['WebSocket', 'create_connection']
 
 """
 websocket python client.
diff --git a/websocket/_handshake.py b/websocket/_handshake.py
index cba48ec..73c9e7f 100644
--- a/websocket/_handshake.py
+++ b/websocket/_handshake.py
@@ -19,21 +19,21 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
     Boston, MA  02110-1335  USA
 
 """
-
-import six
-if six.PY3:
-    from base64 import encodebytes as base64encode
-else:
-    from base64 import encodestring as base64encode
-
 import hashlib
 import hmac
 import os
 
-from ._logging import *
-from ._socket import*
-from ._http import *
+import six
+
 from ._exceptions import *
+from ._http import *
+from ._logging import *
+from ._socket import *
+
+if six.PY3:
+    from base64 import encodebytes as base64encode
+else:
+    from base64 import encodestring as base64encode
 
 __all__ = ["handshake_response", "handshake"]
 
diff --git a/websocket/_http.py b/websocket/_http.py
index 4f9c3e3..88f313a 100644
--- a/websocket/_http.py
+++ b/websocket/_http.py
@@ -19,24 +19,24 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
     Boston, MA  02110-1335  USA
 
 """
-
-import six
-import socket
 import errno
 import os
+import socket
 import sys
 
+import six
+
+from ._exceptions import *
+from ._logging import *
+from ._socket import*
+from ._ssl_compat import *
+from ._url import *
+
 if six.PY3:
     from base64 import encodebytes as base64encode
 else:
     from base64 import encodestring as base64encode
 
-from ._logging import *
-from ._url import *
-from ._socket import*
-from ._exceptions import *
-from ._ssl_compat import *
-
 __all__ = ["proxy_info", "connect", "read_headers"]
 
 
diff --git a/websocket/_logging.py b/websocket/_logging.py
index 321e24a..d440bf7 100644
--- a/websocket/_logging.py
+++ b/websocket/_logging.py
@@ -19,7 +19,6 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
     Boston, MA  02110-1335  USA
 
 """
-
 import logging
 
 _logger = logging.getLogger('websocket')
diff --git a/websocket/_socket.py b/websocket/_socket.py
index f2bc4f1..e2e1dd2 100644
--- a/websocket/_socket.py
+++ b/websocket/_socket.py
@@ -19,13 +19,13 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
     Boston, MA 02110-1335  USA
 
 """
-
 import socket
+
 import six
 
 from ._exceptions import *
-from ._utils import *
 from ._ssl_compat import *
+from ._utils import *
 
 DEFAULT_SOCKET_OPTION = [(socket.SOL_TCP, socket.TCP_NODELAY, 1)]
 if hasattr(socket, "SO_KEEPALIVE"):
diff --git a/websocket/_ssl_compat.py b/websocket/_ssl_compat.py
index d41ca79..0304816 100644
--- a/websocket/_ssl_compat.py
+++ b/websocket/_ssl_compat.py
@@ -19,7 +19,6 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
     Boston, MA 02110-1335  USA
 
 """
-
 __all__ = ["HAVE_SSL", "ssl", "SSLError"]
 
 try:
diff --git a/websocket/_url.py b/websocket/_url.py
index 7299e5c..11216b6 100644
--- a/websocket/_url.py
+++ b/websocket/_url.py
@@ -19,9 +19,9 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
     Boston, MA  02110-1335  USA
 
 """
+import os
 
 from six.moves.urllib.parse import urlparse
-import os
 
 __all__ = ["parse_url", "get_proxy_info"]
 
diff --git a/websocket/_utils.py b/websocket/_utils.py
index 0c939f8..399fb89 100644
--- a/websocket/_utils.py
+++ b/websocket/_utils.py
@@ -19,7 +19,6 @@ Copyright (C) 2010 Hiroki Ohtani(liris)
     Boston, MA 02110-1335  USA
 
 """
-
 import six
 
 __all__ = ["NoLock", "validate_utf8", "extract_err_message"]
diff --git a/websocket/tests/test_websocket.py b/websocket/tests/test_websocket.py
index 20de24c..d2170ae 100644
--- a/websocket/tests/test_websocket.py
+++ b/websocket/tests/test_websocket.py
@@ -1,40 +1,39 @@
 # -*- coding: utf-8 -*-
 #
 
-import six
 import sys
 sys.path[0:0] = [""]
 
 import os
 import os.path
 import socket
-try:
-    from ssl import SSLError
-except ImportError:
-    # dummy class of SSLError for ssl none-support environment.
-    class SSLError(Exception):
-        pass
 
-if sys.version_info[0] == 2 and sys.version_info[1] < 7:
-    import unittest2 as unittest
-else:
-    import unittest
+import six
 
+# websocket-client
+import websocket as ws
+from websocket._handshake import _create_sec_websocket_key, \
+    _validate as _validate_header
+from websocket._http import read_headers
+from websocket._url import get_proxy_info, parse_url
+from websocket._utils import validate_utf8
 
 if six.PY3:
     from base64 import decodebytes as base64decode
 else:
     from base64 import decodestring as base64decode
 
+if sys.version_info[0] == 2 and sys.version_info[1] < 7:
+    import unittest2 as unittest
+else:
+    import unittest
 
-# websocket-client
-import websocket as ws
-from websocket._handshake import _create_sec_websocket_key
-from websocket._url import parse_url, get_proxy_info
-from websocket._utils import validate_utf8
-from websocket._handshake import _validate as _validate_header
-from websocket._http import read_headers
-
+try:
+    from ssl import SSLError
+except ImportError:
+    # dummy class of SSLError for ssl none-support environment.
+    class SSLError(Exception):
+        pass
 
 # Skip test to access the internet.
 TEST_WITH_INTERNET = os.environ.get('TEST_WITH_INTERNET', '0') == '1'