public DeleteDeliveryCommandHandler(
     IDeliveryRepository deliveryRepository,
     IExistsDeliverySpecification existsDelivery,
     IUserContext userContext,
     IUnitOfWork unitOfWork)
 {
     _deliveryRepository = deliveryRepository;
     _existsDelivery     = existsDelivery;
     _userContext        = userContext;
     _unitOfWork         = unitOfWork;
 }