public ProcessingResult ValidateTaxYearStructure(TaxPeriod taxPeriod) { var finPeriodWithSameStartDate = _gafRepository.FindFinPeriodWithStartDate(taxPeriod.StartDate); var finPeriodWithSameEndDate = _gafRepository.FindFinPeriodWithEndDate(taxPeriod.EndDate); if (finPeriodWithSameStartDate == null || finPeriodWithSameEndDate == null) { var result = new ProcessingResult(); result.AddErrorMessage(Messages.TheGAFFileCannotBePrepared); return(result); } return(ProcessingResult.Success); }