Message

Element 'cbc:ChargeIndicator' MUST contain value 'false'.

Context
/ubl:Invoice/cac:InvoiceLine/cac:Price/cac:AllowanceCharge/cbc:ChargeIndicator
Test
normalize-space(text()) = 'false'
Usage
/ ubl:Invoice / cac:InvoiceLine / cac:Price / cac:AllowanceCharge / cbc:ChargeIndicator