    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:186)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compare(StructureDefinitionComparer.java:120)
    	at org.hl7.fhir.r5.comparison.ComparisonSession.compare(ComparisonSession.java:107)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.intersectTypes(StructureDefinitionComparer.java:1038)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareElements(StructureDefinitionComparer.java:270)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareChildren(StructureDefinitionComparer.java:377)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareElements(StructureDefinitionComparer.java:286)
    	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compare(StructureDefinitionComparer.java:164)
    	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.PublisherProcessor.checkConformanceResources(PublisherProcessor.java:1500)
    	at org.hl7.fhir.igtools.publisher.PublisherProcessor.loadConformance2(PublisherProcessor.java:104)
    	at org.hl7.fhir.igtools.publisher.Publisher.createIg(Publisher.java:404)
    	at org.hl7.fhir.igtools.publisher.Publisher.execute(Publisher.java:233)
    	at org.hl7.fhir.igtools.publisher.Publisher.main(Publisher.java:1616)