remove unnecessary allow_none=True

IPython/config/application.py

@@ -174,7 +174,7 b' class Application(SingletonConfigurable):'
         _log_handler.setFormatter(_log_formatter)
     
 
-    log = Instance(logging.Logger, allow_none=True)
+    log = Instance(logging.Logger)
     def _log_default(self):
         """Start logging for this application.
 

IPython/config/configurable.py

@@ -372,7 +372,7 b' class LoggingConfigurable(Configurable):'
     is to get the logger from the currently running Application.
     """
 
-    log = Instance('logging.Logger', allow_none=True)
+    log = Instance('logging.Logger')
     def _log_default(self):
         from IPython.utils import log
         return log.get_logger()

IPython/core/interactiveshell.py

@@ -301,7 +301,7 b' class InteractiveShell(SingletonConfigurable):'
     data_pub_class = None
 
     exit_now = CBool(False)
-    exiter = Instance(ExitAutocall, allow_none=True)
+    exiter = Instance(ExitAutocall)
     def _exiter_default(self):
         return ExitAutocall(self)
     # Monotonically increasing execution counter
@@ -453,7 +453,7 b' class InteractiveShell(SingletonConfigurable):'
 
 
     # Private interface
-    _post_execute = Instance(dict, allow_none=True)
+    _post_execute = Dict()
 
     # Tracks any GUI loop loaded for pylab
     pylab_gui_select = None

IPython/html/services/clusters/clustermanager.py

@@ -20,7 +20,7 b' class ClusterManager(LoggingConfigurable):'
     delay = Float(1., config=True,
         help="delay (in s) between starting the controller and the engines")
 
-    loop = Instance('zmq.eventloop.ioloop.IOLoop', allow_none=True)
+    loop = Instance('zmq.eventloop.ioloop.IOLoop')
     def _loop_default(self):
         from zmq.eventloop.ioloop import IOLoop
         return IOLoop.instance()

IPython/kernel/zmq/zmqshell.py

@@ -367,7 +367,7 b' class ZMQInteractiveShell(InteractiveShell):'
     # will print a warning in the absence of readline.
     autoindent = CBool(False)
 
-    exiter = Instance(ZMQExitAutocall, allow_none=True)
+    exiter = Instance(ZMQExitAutocall)
     def _exiter_default(self):
         return ZMQExitAutocall(self)
     

ipython_parallel/apps/baseapp.py

@@ -123,7 +123,7 b' class BaseParallelApplication(BaseIPythonApplication):'
     def _config_files_default(self):
         return ['ipcontroller_config.py', 'ipengine_config.py', 'ipcluster_config.py']
     
-    loop = Instance('zmq.eventloop.ioloop.IOLoop', allow_none=True)
+    loop = Instance('zmq.eventloop.ioloop.IOLoop')
     def _loop_default(self):
         from zmq.eventloop.ioloop import IOLoop
         return IOLoop.instance()

ipython_parallel/apps/logwatcher.py

@@ -52,7 +52,7 b' class LogWatcher(LoggingConfigurable):'
     # internals
     stream = Instance('zmq.eventloop.zmqstream.ZMQStream', allow_none=True)
     
-    context = Instance(zmq.Context, allow_none=True)
+    context = Instance(zmq.Context)
     def _context_default(self):
         return zmq.Context.instance()
     

ipython_parallel/controller/heartmonitor.py

@@ -79,7 +79,7 b' class HeartMonitor(LoggingConfigurable):'
 
     pingstream=Instance('zmq.eventloop.zmqstream.ZMQStream', allow_none=True)
     pongstream=Instance('zmq.eventloop.zmqstream.ZMQStream', allow_none=True)
-    loop = Instance('zmq.eventloop.ioloop.IOLoop', allow_none=True)
+    loop = Instance('zmq.eventloop.ioloop.IOLoop')
     def _loop_default(self):
         return ioloop.IOLoop.instance()