protected override void ValidateAdd(ref StringBuilder validationErrors, CustomerDTO customerBO)
        {
            if (!customerBO.IsNew())
            {
                validationErrors.Append("La ressource que vous souhaitez ajouter existe déjà.");
                return;
            }
            var validationResult = new CustomerValidator().Validate(customerBO);

            validationErrors.Append(validationResult.ToString());
        }