Value MUST be part of code list 'Allowance reason codes (UNCL5189 subset)' or 'Charge reason code (UNCL7161)'.
/ubl:Invoice/cac:InvoiceLine/cac:AllowanceCharge/cbc:AllowanceChargeReasonCode(some $code in $clUNCL5189 satisfies $code = normalize-space(text())) or (some $code in $clUNCL7161 satisfies $code = normalize-space(text()))