    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:197)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compare(StructureDefinitionComparer.java:131)
    	at org.hl7.fhir.r5.comparison.ComparisonSession.compare(ComparisonSession.java:107)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.intersectTypes(StructureDefinitionComparer.java:1040)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareElements(StructureDefinitionComparer.java:281)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareChildren(StructureDefinitionComparer.java:384)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareElements(StructureDefinitionComparer.java:297)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compare(StructureDefinitionComparer.java:175)
    	at org.hl7.fhir.r5.comparison.ComparisonSession.compare(ComparisonSession.java:107)
    	at org.hl7.fhir.igtools.publisher.comparators.PreviousVersionComparator.finishChecks(PreviousVersionComparator.java:266)
    	at org.hl7.fhir.igtools.publisher.Publisher.checkConformanceResources(Publisher.java:6702)
    	at org.hl7.fhir.igtools.publisher.Publisher.loadConformance2(Publisher.java:6485)
    	at org.hl7.fhir.igtools.publisher.Publisher.createIg(Publisher.java:1168)
    	at org.hl7.fhir.igtools.publisher.Publisher.execute(Publisher.java:1023)
    	at org.hl7.fhir.igtools.publisher.Publisher.main(Publisher.java:15805)
    	at org.hl7.fhir.igtools.web.PublicationProcess.runBuild(PublicationProcess.java:1101)
    	at org.hl7.fhir.igtools.web.PublicationProcess.doPublish(PublicationProcess.java:557)
    	at org.hl7.fhir.igtools.web.PublicationProcess.publishInner2(PublicationProcess.java:470)
    	at org.hl7.fhir.igtools.web.PublicationProcess.publishInner(PublicationProcess.java:286)
    	at org.hl7.fhir.igtools.web.PublicationProcess.publish(PublicationProcess.java:146)
    	at org.hl7.fhir.igtools.publisher.Publisher.main(Publisher.java:15553)