[C++-sig] pyCXX example of a callback

[apocalypznow]

Hi,

Can anyone post a simple pyCXX example of a callback into python?  My 
python function should allow a string passed as a parameter, and returns 
a string, ie:

def somepythonCB(s_in):
     s_out = dosomethingtoinputstringandreturnoutputstring(s_in)
     return s_out


Much appreciated, thanks.