public async Task AddNewSubscriber(CreateSubscriberRequest request) { var(email, subscribed) = request; if (string.IsNullOrWhiteSpace(email)) { throw new ArgumentNullException(email); } try { await _subscriberRepository.AddNewSubscriber(email, subscribed); } catch (Exception ex) { if (ex.Message.Contains("PRIMARY KEY")) { throw new DuplicateEmailException(); } } }