<?php     private function generateRowKey(InvoiceDetails $row): string
    {
        return implode('-', [
            $row->getVatCategory()->value ?? '',
            $row->getVatExemptionCategory()->value ?? '',
            $row->getWithheldPercentCategory()->value ?? '',
            $row->getFeesPercentCategory()->value ?? '',
            $row->getOtherTaxesPercentCategory()->value ?? '',
            $row->getStampDutyPercentCategory()->value ?? '',
            $row->getNotVAT195() ? '1' : '',
        ]);
    }