How to write an API for a Python application?

[Gary Kshepitzki]

Hello
I would like to create an API for a piece of Python code. The API is for use 
by non Python code.
It should support interaction in both directions, both accessing functions 
on the API and the ability for the API to raise events on its client.
What is the best way to do that?
I though of doing it as a python COM server but I am not familiar with COM 
and I saw that implementing a COM server with events in python is not 
trivial for me.
Is there a better (or simpler) solution?
What are the common ways for doing that?

Any answer would be highly appreciated.
Regards
Gary