fix error in doc (arg->kwarg) and pep-8

IPython/config/configurable.py

@@ -72,7 +72,7 b' class Configurable(HasTraits):'
 
             class MyConfigurable(Configurable):
                 def __init__(self, config=None):
-                    super(MyConfigurable, self).__init__(config)
+                    super(MyConfigurable, self).__init__(config=config)
                     # Then any other code you need to finish initialization.
 
         This ensures that instances will be configured properly.

IPython/core/application.py

@@ -35,13 +35,11 b' import shutil'
 import sys
 
 from IPython.config.application import Application, catch_config_error
-from IPython.config.configurable import Configurable
-from IPython.config.loader import Config, ConfigFileNotFound
+from IPython.config.loader import ConfigFileNotFound
 from IPython.core import release, crashhandler
 from IPython.core.profiledir import ProfileDir, ProfileDirError
 from IPython.utils.path import get_ipython_dir, get_ipython_package_dir
 from IPython.utils.traitlets import List, Unicode, Type, Bool, Dict
-from IPython.utils import py3compat
 
 #-----------------------------------------------------------------------------
 # Classes and functions