private Map<String, Map<String, Map<SchemaInternalOperation, List<SchemaCharge>>>> splitTotal(List<SchemaCharge> charges) {
    return MapSeq.map(splitByOffer(charges), (String k, List<SchemaCharge> v) -> {
        return MapSeq.map(splitByResource(v), w -> splitByOperation(w));
    });
}

private Map<String, List<SchemaCharge>> splitByOffer(List<SchemaCharge> charges) {
    return MapSeq.orderedGroupBy(charges, SchemaCharge::getOfferId);
}

private Map<String, List<SchemaCharge>> splitByResource(List<SchemaCharge> charges) {
    Map<String, List<SchemaCharge>> map = MapSeq.orderedGroupBy(charges, SchemaCharge::getSku);
    return MapSeq.map(
            map,
            chs -> chs.stream()
                    .sorted(Comparator.comparing(
                            ch -> ch.getStartDate()
                                    .map(Optional::of)
                                    .orElseGet(ch::getShipmentDate)
                                    .map(LocalDate::parse)
                                    .orElseGet(() -> LocalDate.from(ch.getCreateDatetime()))
                    ))
                    .collect(Collectors.toList())
    );
}

private Map<SchemaInternalOperation, List<SchemaCharge>> splitByOperation(List<SchemaCharge> charges) {
    return MapSeq.orderedGroupBy(charges, SchemaCharge::getOperation);
}