For Swedish suppliers using Plusgiro, the Account ID must be numeric
//cac:PaymentMeans[//cac:AccountingSupplierParty/cac:Party[cac:PostalAddress/cac:Country/cbc:IdentificationCode = 'SE'] and normalize-space(cbc:PaymentMeansCode) = '30' and normalize-space(cac:PayeeFinancialAccount/cac:FinancialInstitutionBranch/cbc:ID) = 'SE:PLUSGIRO']/cac:PayeeFinancialAccount/cbc:ID
string(number(normalize-space(.))) != 'NaN'