string_str(PyObject *s)
{
    assert(PyString_Check(s));
    if (PyString_CheckExact(s)) {
        Py_INCREF(s);
        return s;
    }
    else {
        /* Subtype -- return genuine string with the same value. */
        PyStringObject *t = (PyStringObject *) s;
        return PyString_FromStringAndSize(t->ob_sval, Py_SIZE(t));
    }
}
Unknown