static void deleteConcepts(L conceptsOrIDs) {
  db_mainConcepts().deleteConcepts(conceptsOrIDs);
}

static <A extends Concept> L<A> deleteConcepts(Class<A> c, O... params) {
  L<A> l = findConceptsWhere(c, params);
  deleteConcepts(l);
  ret l;
}