pub fn is_stored(attrs: Raw) -> bool {
    if (attrs & UNDEFS) != 0 {
        return false;
    }
    if (attrs & DATA) != 0 {
        return (attrs & ACCESSOR) == 0;
    }
    if (attrs & ACCESSOR) != 0 {
        return (attrs & WRITABLE) == 0;
    }
    false
}

pub fn remove_undefs(attrs: Raw) -> Raw {
    attrs & !(UNDEFS)