public void Add(string name, string businessName, string businessNumber) { if (!string.IsNullOrWhiteSpace(businessNumber)) { if (!_partnerRepository.BusinessNumberExists(businessNumber)) { Partner partnerDomainModel = Partner.CreateNewPartner(name, businessName, businessNumber); _partnerRepository.Add(partnerDomainModel); return; } throw new Exception("BusinessNumber already exists"); } throw new Exception("BusinessNumber cannot be null or empty"); }