Advice on Python C modules

[Torsten Marek]

Hello all,

I think about rewriting one C++ library with Python wrappers (by sip) to 
  a pure Python module (because I just use it from Python).

I have to create custom types and inherit from those custom types.
Is it better to use pure C for that module, Pyrex or should I stay with 
my current library (which has to be modified for some other reasons, too)?

thanks for your time

greets

Torsten