static <A extends Concept> ConceptFieldIndexCI<A> getConceptFieldCIIndex(Class<A> c, S field) {
  ret getConceptFieldCIIndex(db_mainConcepts(), c, field);
}

static <A extends Concept> ConceptFieldIndexCI<A> getConceptFieldCIIndex(Concepts concepts, Class<A> c, S field) {
  ret (ConceptFieldIndexCI) concepts.getCIFieldIndex(c, field);
}