Do you mean to always set `PyTuple_SetItem` with `full_slice` and set it again with `section_slice` for `i==axis`?
```
Py_INCREF(full_slice);
PyTuple_SetItem(slice_tuple, i, full_slice);
if(i==axis)
{
    Py_INCREF(section_slice);  
    PyTuple_SetItem(slice_tuple, i, section_slice);
}