Improve docstring for InProcessHBChannel

IPython/kernel/inprocess/channels.py

@@ -1,95 +1,100 b''
 """A kernel client for in-process kernels."""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from IPython.kernel.channelsabc import (
     ShellChannelABC, IOPubChannelABC,
     HBChannelABC, StdInChannelABC,
 )
 
 from .socket import DummySocket
 
 #-----------------------------------------------------------------------------
 # Channel classes
 #-----------------------------------------------------------------------------
 
 class InProcessChannel(object):
     """Base class for in-process channels."""
     proxy_methods = []
 
     def __init__(self, client=None):
         super(InProcessChannel, self).__init__()
         self.client = client
         self._is_alive = False
 
     def is_alive(self):
         return self._is_alive
 
     def start(self):
         self._is_alive = True
 
     def stop(self):
         self._is_alive = False
 
     def call_handlers(self, msg):
         """ This method is called in the main thread when a message arrives.
 
         Subclasses should override this method to handle incoming messages.
         """
         raise NotImplementedError('call_handlers must be defined in a subclass.')
 
     def flush(self, timeout=1.0):
         pass
 
 
     def call_handlers_later(self, *args, **kwds):
         """ Call the message handlers later.
 
         The default implementation just calls the handlers immediately, but this
         method exists so that GUI toolkits can defer calling the handlers until
         after the event loop has run, as expected by GUI frontends.
         """
         self.call_handlers(*args, **kwds)
 
     def process_events(self):
         """ Process any pending GUI events.
 
         This method will be never be called from a frontend without an event
         loop (e.g., a terminal frontend).
         """
         raise NotImplementedError
 
 
 
 class InProcessHBChannel(object):
-    """See `IPython.kernel.channels.HBChannel` for docstrings."""
+    """A dummy heartbeat channel interface for in-process kernels.
+
+    Normally we use the heartbeat to check that the kernel process is alive.
+    When the kernel is in-process, that doesn't make sense, but clients still
+    expect this interface.
+    """
 
     time_to_dead = 3.0
 
     def __init__(self, client=None):
         super(InProcessHBChannel, self).__init__()
         self.client = client
         self._is_alive = False
         self._pause = True
 
     def is_alive(self):
         return self._is_alive
 
     def start(self):
         self._is_alive = True
 
     def stop(self):
         self._is_alive = False
 
     def pause(self):
         self._pause = True
 
     def unpause(self):
         self._pause = False
 
     def is_beating(self):
         return not self._pause
 
 
 HBChannelABC.register(InProcessHBChannel)