The given example function initspam fails if an 

Based on some experience with my own code, I have found out that the
function import_spam() fails when the module is not importable. In this
case, it returns 0, although it should return -1 when an error occurs.

This causes a standalone program to crash if it has a main() function like:

    Py_Initialize();
    if (import_spam() < 0) {
        Py_Finalize();
        return 1;
    }
    Py_Finalize();

The function should return -1, so we can know there is an error and are
able to handle it.