Message

[PEPPOL-T001-R023] listID for PreferredLanguageLocaleCode MUST be 'ISO639-1'.

Context
ubl:ExpressionOfInterestRequest/cbc:PreferredLanguageLocaleCode
Test
normalize-space(./@listID) = 'ISO639-1'
Usage
/ t001:ExpressionOfInterestRequest / cbc:PreferredLanguageLocaleCode / @listID