func (v *List) NthData(n uint) interface{} {
	ptr := v.nthDataRaw(n)
	if v.dataWrap != nil {
		return v.dataWrap(ptr)
	}
	return ptr
}
func (v *List) NthData(n uint) interface{} {
	ptr := v.nthDataRaw(n)
	if v.dataWrap != nil {
		return v.dataWrap(ptr)
	}
	return ptr
}
// NthDataWrapped acts the same as g_list_nth_data(), but passes
// retrieved value before returning through wrap function, set by DataWrapper().
// If no wrap function is set, it returns raw unsafe.Pointer.