java.lang.NullPointerException
	at org.hl7.fhir.r5.comparison.ValueSetComparer.findInList(ValueSetComparer.java:196)
	at org.hl7.fhir.r5.comparison.ValueSetComparer.compareCompose(ValueSetComparer.java:139)
	at org.hl7.fhir.r5.comparison.ValueSetComparer.compare(ValueSetComparer.java:128)
	at org.hl7.fhir.r5.comparison.ComparisonSession.compare(ComparisonSession.java:87)
	at org.hl7.fhir.igtools.publisher.PreviousVersionComparator.finishChecks(PreviousVersionComparator.java:250)
	at org.hl7.fhir.igtools.publisher.Publisher.checkConformanceResources(Publisher.java:3926)
	at org.hl7.fhir.igtools.publisher.Publisher.loadConformance(Publisher.java:3832)
	at org.hl7.fhir.igtools.publisher.Publisher.createIg(Publisher.java:877)
	at org.hl7.fhir.igtools.publisher.Publisher.execute(Publisher.java:732)
	at org.hl7.fhir.igtools.publisher.Publisher.main(Publisher.java:8417)