def _algo_fill_zi_if_missing(ro_rw_zi):
    """Create an empty zi section if it is missing"""
    s_ro, s_rw, s_zi = ro_rw_zi
    if s_rw is None:
        return ro_rw_zi
    if s_zi is not None:
        return ro_rw_zi
    s_zi = {
        "sh_addr": s_rw["sh_addr"] + s_rw["sh_size"],
        "sh_size": 0
    }
    return s_ro, s_rw, s_zi