diff -r d8b66e3fd335 -r 3a84a79c4ed5 cubicweb/cwconfig.py
--- a/cubicweb/cwconfig.py	Thu Nov 24 16:58:27 2016 +0100
+++ b/cubicweb/cwconfig.py	Thu Nov 24 16:58:50 2016 +0100
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# copyright 2003-2012 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# copyright 2003-2016 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
 # contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
 #
 # This file is part of CubicWeb.
@@ -177,10 +177,9 @@
 
    Directory where pid files will be written
 """
+
 from __future__ import print_function
 
-
-
 import importlib
 import logging
 import logging.config
@@ -194,7 +193,7 @@
 import stat
 import sys
 from threading import Lock
-from warnings import warn, filterwarnings
+from warnings import filterwarnings
 
 from six import text_type
 
@@ -220,6 +219,7 @@
     except IndexError:
         raise ConfigurationError('no such config %r (check it exists with "cubicweb-ctl list")' % name)
 
+
 def possible_configurations(directory):
     """return a list of installed configurations in a directory
     according to \*-ctl files
@@ -227,6 +227,7 @@
     return [name for name in ('repository', 'all-in-one')
             if exists(join(directory, '%s.conf' % name))]
 
+
 def guess_configuration(directory):
     """try to guess the configuration to use for a directory. If multiple
     configurations are found, ConfigurationError is raised
@@ -237,6 +238,7 @@
                                  % (directory, modes))
     return modes[0]
 
+
 def _find_prefix(start_path=None):
     """Return the prefix path of CubicWeb installation.