Changes to PyLong_FromUnsignedLong and PyLong_FromUnsignedLongLong applied. I've left the others; for the small int initialisation, that code isn't performance critical anyway, and I'm not entirely comfortable with assuming that PyObject_INIT_VAR will always handle negative sizes correctly. (The (ab)use of the sign bit of the ob_size field is something that's particular to the int type.)