List<User> users = this.userRepository.findAllByProductsToBuyIsNotNullOrderByLastNameFirstName()
                .stream()
                .filter(user -> {
                    return user.getProductsToSell().stream()
                            .filter(product -> product.getBuyerId()!=null)
                            .count() >0;

                })
                .collect(Collectors.toList());

        users.forEach(user -> {

        });