public async Task <Unit> Handle(ChangeSubscriptionExpirationDateForMemberCommand command, CancellationToken cancellationToken)
        {
            MemberSubscription memberSubscription = await _memberSubscriptionRepository.GetByIdOptionalAsync(new MemberSubscriptionId(command.MemberId.Value));

            if (memberSubscription == null)
            {
                memberSubscription = MemberSubscription.CreateForMember(command.MemberId, command.ExpirationDate);
                await _memberSubscriptionRepository.AddAsync(memberSubscription);
            }
            else
            {
                memberSubscription.ChangeExpirationDate(command.ExpirationDate);
            }

            return(Unit.Value);
        }