public async Task <Unit> Handle(ConfirmRegistrationCommand command, CancellationToken cancellationToken)
        {
            var registration =
                await _customerRegistrationRepository.GetByIdAsync(
                    new CustomerRegistrationId(command.CustomerRegistrationId));

            registration.Confirm(command.ActivationCode);

            return(Unit.Value);
        }
        public async Task Handle(CustomerRegistrationConfirmedDomainEvent @event, CancellationToken cancellationToken)
        {
            var registration = await _customerRegistrationRepository.GetByIdAsync(
                new CustomerRegistrationId(@event.CustomerRegistrationId.Value)
                );

            var customer = registration.CreateCustomer(_customerChecker);

            await _customerRepository.AddAsync(customer);
        }