svoid nuLike onConceptChangeByClass(Class type, Runnable r) {
  onConceptChangeByClass(db_mainConcepts(), type, r);
}

svoid onConceptChangeByClass(Concepts cc, Class type, Runnable r) {
  onConceptChangeByClass_notOnAllChanged(cc, type, r);
  cc.onAllChanged.add(r);
}