846 static PyObject *
847 bitarray_extend(bitarrayobject *self, PyObject *obj)
848 {
849     if (extend_dispatch(self, obj) < 0)
when considering range: -0x80000000 <= value <= -1
taking True path
850         return NULL;
851     Py_RETURN_NONE;
852 }
returning (PyObject*)NULL without setting an exception