currentOpcode_Is_CallMethNoArgs dereferences a NULL pointer

static bool currentOpcode_Is_CallMethNoArgs()
    // PYSIDE-2221: Special case for the NoGil version:
    //              Find out if we have such a version.
    //              We could also ask the variable `Py_NOGIL`.
    static PyObject *flags = PySys_GetObject("flags");
    static bool isNoGil = PyObject_HasAttrString(flags, "nogil");
    // We look into the currently active operation if we are going to call
    // a method with zero arguments.
    auto *frame = PyEval_GetFrame();
#if !Py_LIMITED_API && !defined(PYPY_VERSION)
    auto *f_code = PyFrame_GetCode(frame);
#else