[ibr-tdd-27] – The cac:InvoicePeriod (BG-14) element at line level, MUST NOT contain elements other than cbc:StartDate (BT-073) and cbc:EndDate (BT-074).
ibr-tdd-27/pxs:TaxData/pxs:ReportedTransaction/pxs:ReportedDocument/pxs:DocumentLine/cac:InvoicePeriodcount(*[not(self::cbc:StartDate or self::cbc:EndDate)]) = 0