private static async Task<IEnumerable<CarrierSummary>> GetCarriersWithDynamicFilters(CarrierQueryFilter filter, IMongoCollection<Carrier> carriers, IMongoCollection<CarrierContract> carrierContracts)
        {
            var query = carriers.AsQueryable().GroupJoin(carrierContracts, x => x.Id, x => x.CarrierId, (carrier, contracts) => new { carrier, contracts });
            Expression<Func<CarrierContract, bool>> predicate = x => true;


            if (!string.IsNullOrWhiteSpace(filter.DestinationCountryCode))
            {
                query = query.Where(x => x.contracts.Any(c => c.DestinationCountryCode == filter.DestinationCountryCode));
                predicate = c => c.DestinationCountryCode == filter.DestinationCountryCode;
            }

            if (!string.IsNullOrWhiteSpace(filter.DistributionCountryCode))
            {
                query = query.Where(x => x.contracts.Any(c => c.DistributionCountryCode == filter.DistributionCountryCode));
                predicate = c => c.DistributionCountryCode == filter.DistributionCountryCode;
            }

            var res = query.Select(x => new CarrierSummary
            {
                Id = x.carrier.Id,
                Name = x.carrier.Name,
                CarrierCode = x.carrier.Code,
                DeliveryTypes = x.contracts.AsQueryable().Where(predicate).Select(y => y.DeliveryType)
            });

            return await res.ToListAsync();
        }