Modify a C++ instance from the embed python interpreter

[Wezzy]

Hi, is there a tool that automatically expose an object to python? i
have an instance of a C++ (or ObjC) object and i want to pass it to the
embed interpreter that runs inside my program.
Python code have to call c++ method and register some callback.

I know that swig helps when python creates c++ instance but i've the
instance and i want to use it with python.

Thanks

-- 
Ciao
Fabio