context PurposeActivity
inv: not self.code.oclIsUndefined() and 
self.code.nullFlavor.oclIsUndefined() and
(not self.code.code.oclIsUndefined()) and self.code.code='23745001' and 
(not self.code.codeSystem.oclIsUndefined()) and self.code.codeSystem='2.16.840.1.113883.6.96' and
(not self.code.displayName.oclIsUndefined()) and self.code.displayName='Documentation procedure' and 
(self.code.codeSystemName.oclIsUndefined()) and self.code.codeSystemName='SNOMED CT'