[C++-sig] python override of C++ virtual mem fun not exactly working yet

[DRandallTaylor]

I've added the invocation of the base class constructor (thanks Stefan):

class InboxListener(Callback):
	def __init__(self, sess):
		Callback.__init__(self)
		self.inbox = sess.CreateInbox(self)  # ArgumentError here
	def OnData():
		print "OnData called"

But I still get this:


ArgumentError: Python argument types in
    VIAmSession.CreateInbox(Session, InboxListener)
did not match C++ signature:
    CreateInbox(class Session {lvalue}, class Callback {lvalue})


Python does not yet know that my InboxListener is derived from Callback.  How 
shall I tell her?

Cheers.