callbacks in python

[Jonathan Epstein]

I'm working on my first Python project, and am encountering the issue of
callbacks.  In particular, whenever my class undergoes a change which
modifies its print representation, I would like to notify a callback
routine which has been specified by the user of the class.  This
callback routine would usually be some sort of GUI.

Is this the right way to do things in python?  I read a reference in
_Python Programming on Win32_ which seemed to suggest that this was not
the right way to do things, but I am not sure.

Thanks in advance for any help, especially including any pointers to
examples...

- Jonathan