[SCH-EUSR-24] MUST have one Key element with the meta scheme ID 'DT'
SCH-EUSR-24
/eusr:EndUserStatisticsReport/eusr:Subset[normalize-space(@type) = 'PerDT-PR-EUC']
count(eusr:Key[normalize-space(@metaSchemeID) = 'DT']) = 1