When compiling Python C-API extensions with "-Wextra", warnings like 

warning: unused parameter ‘self’ [-Wunused-parameter]

appear for code (like below). It seems like a minor issue for a warning to appear when "PyObject *self, PyObject *args" is required. Is there an underlying issue in the API?

static PyObject *mathfunc_ismersenneprime(PyObject *self, PyObject *args) {
    sllint num;
    ASSERT_LONGLONG_ARG(num);
    if (num < (sllint)0) ERR_POSITIVE_INT;
    returnbool(islonglongmersenneprime(num));
}

> Is there an underlying issue in the API?

You can use self if your code. If you don't need it, you can use Py_UNUSED() macro available since Python 3.4.

Please don't open bug reports to ask questions on your own code. The bug tracker is not forum.

Thank you and sorry.

New changeset 2138163621196a186975796afb2b0a6aa335231d by Victor Stinner (Petr Viktorin) in branch 'master':
bpo-29179: Document the Py_UNUSED macro (#4341)
https://github.com/python/cpython/commit/2138163621196a186975796afb2b0a6aa335231d