    org.hl7.fhir.exceptions.DefinitionException: StructureDefinition is not for an profile - can't be compared (left: Identifier)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.check(StructureDefinitionComparer.java:193)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compare(StructureDefinitionComparer.java:129)
    	at org.hl7.fhir.r5.comparison.ComparisonSession.compare(ComparisonSession.java:107)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.intersectTypes(StructureDefinitionComparer.java:987)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareElements(StructureDefinitionComparer.java:277)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareChildren(StructureDefinitionComparer.java:380)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareElements(StructureDefinitionComparer.java:293)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compare(StructureDefinitionComparer.java:173)
    	at org.hl7.fhir.r5.comparison.ComparisonSession.compare(ComparisonSession.java:107)
    	at org.hl7.fhir.igtools.publisher.comparators.PreviousVersionComparator.finishChecks(PreviousVersionComparator.java:262)
    	at org.hl7.fhir.igtools.publisher.Publisher.checkConformanceResources(Publisher.java:6396)
    	at org.hl7.fhir.igtools.publisher.Publisher.loadConformance2(Publisher.java:6202)
    	at org.hl7.fhir.igtools.publisher.Publisher.createIg(Publisher.java:1196)
    	at org.hl7.fhir.igtools.publisher.Publisher.execute(Publisher.java:1032)
    	at org.hl7.fhir.igtools.publisher.Publisher.main(Publisher.java:14935)
    	at org.hl7.fhir.igtools.web.PublicationProcess.runBuild(PublicationProcess.java:1003)
    	at org.hl7.fhir.igtools.web.PublicationProcess.doPublish(PublicationProcess.java:512)
    	at org.hl7.fhir.igtools.web.PublicationProcess.publishInner2(PublicationProcess.java:425)
    	at org.hl7.fhir.igtools.web.PublicationProcess.publishInner(PublicationProcess.java:237)
    	at org.hl7.fhir.igtools.web.PublicationProcess.publish(PublicationProcess.java:127)
    	at org.hl7.fhir.igtools.publisher.Publisher.main(Publisher.java:14693)