old_contents: """Abstract base class for kernel managers."""
  
  #-----------------------------------------------------------------------------
  #  Copyright (C) 2013  The IPython Development Team
  #
  #  Distributed under the terms of the BSD License.  The full license is in
  #  the file COPYING, distributed as part of this software.
  #-----------------------------------------------------------------------------
  
  import abc
  
  from IPython.utils.py3compat import with_metaclass
  
  
  class KernelManagerABC(with_metaclass(abc.ABCMeta, object)):
      """KernelManager ABC.
  
      The docstrings for this class can be found in the base implementation:
  
      `IPython.kernel.kernelmanager.KernelManager`
      """
  
      @abc.abstractproperty
      def kernel(self):
          pass
  
      @abc.abstractproperty
      def shell_channel_class(self):
          pass
  
      @abc.abstractproperty
      def iopub_channel_class(self):
          pass
  
      @abc.abstractproperty
      def hb_channel_class(self):
          pass
  
      @abc.abstractproperty
      def stdin_channel_class(self):
          pass
  
      #--------------------------------------------------------------------------
      # Channel management methods
      #--------------------------------------------------------------------------
  
      @abc.abstractmethod
      def start_channels(self, shell=True, iopub=True, stdin=True, hb=True):
          pass
  
      @abc.abstractmethod
      def stop_channels(self):
          pass
  
      @abc.abstractproperty
      def channels_running(self):
          pass
  
      @abc.abstractproperty
      def shell_channel(self):
          pass
  
      @abc.abstractproperty
      def iopub_channel(self):
          pass
  
      @abc.abstractproperty
      def stdin_channel(self):
          pass
  
      @abc.abstractproperty
      def hb_channel(self):
          pass
  
      #--------------------------------------------------------------------------
      # Kernel management
      #--------------------------------------------------------------------------
  
      @abc.abstractmethod
      def start_kernel(self, **kw):
          pass
  
      @abc.abstractmethod
      def shutdown_kernel(self, now=False, restart=False):
          pass
  
      @abc.abstractmethod
      def restart_kernel(self, now=False, **kw):
          pass
  
      @abc.abstractproperty
      def has_kernel(self):
          pass
  
      @abc.abstractmethod
      def interrupt_kernel(self):
          pass
  
      @abc.abstractmethod
      def signal_kernel(self, signum):
          pass
  
      @abc.abstractmethod
      def is_alive(self):
          pass
  
new_contents: """Abstract base class for kernel managers."""
  
  # Copyright (c) IPython Development Team.
  # Distributed under the terms of the Modified BSD License.
  
  import abc
  
  from IPython.utils.py3compat import with_metaclass
  
  
  class KernelManagerABC(with_metaclass(abc.ABCMeta, object)):
      """KernelManager ABC.
  
      The docstrings for this class can be found in the base implementation:
  
      `IPython.kernel.kernelmanager.KernelManager`
      """
  
      @abc.abstractproperty
      def kernel(self):
          pass
  
      #--------------------------------------------------------------------------
      # Kernel management
      #--------------------------------------------------------------------------
  
      @abc.abstractmethod
      def start_kernel(self, **kw):
          pass
  
      @abc.abstractmethod
      def shutdown_kernel(self, now=False, restart=False):
          pass
  
      @abc.abstractmethod
      def restart_kernel(self, now=False, **kw):
          pass
  
      @abc.abstractproperty
      def has_kernel(self):
          pass
  
      @abc.abstractmethod
      def interrupt_kernel(self):
          pass
  
      @abc.abstractmethod
      def signal_kernel(self, signum):
          pass
  
      @abc.abstractmethod
      def is_alive(self):
          pass
  
subject: remove unused channel definitions from managerabc