@Override
    public void create(DistrictsJSONImportDto model) {
        if (!ValidationUtil.isValid(model)){
            throw new IllegalArgumentException();
        }
        Town town = townRepository.findByName(model.getTownName());
        District district = districtRepository.findByName(model.getName());
        if (district != null){
            throw new IllegalStateException("duplicate data");
        }
        district = mapper.convert(model, District.class);
        district.setTown(town);
        districtRepository.save(district);
    }