No, actually I don't mean to change all the (obj)->ob_type in Python repo. I know there are more (obj)->ob_type in it, but they are compliant with PEP3123 since obj is of type PyObject*. You don't have the need to change them. What I propose is only to change the macros that not use Py_TYPE since the macros may be used later with arguments not of type PyObject*.