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:251) at org.hl7.fhir.igtools.publisher.Publisher.checkConformanceResources(Publisher.java:3941) at org.hl7.fhir.igtools.publisher.Publisher.loadConformance(Publisher.java:3847) at org.hl7.fhir.igtools.publisher.Publisher.createIg(Publisher.java:883) at org.hl7.fhir.igtools.publisher.Publisher.execute(Publisher.java:738) at org.hl7.fhir.igtools.publisher.Publisher.main(Publisher.java:8495)