static <A extends Concept> A findConceptWhere(Class<A> c, O... params) {
  ret findConceptWhere(mainConcepts, c, params);
}

static <A extends Concept> A findConceptWhere(Concepts concepts, Class<A> c, O... params) {
  params = expandParams(c, params);
  for (A x : concepts.list(c))
    if (checkConceptFields(x, params))
      ret x;
  ret null;
}