static S callStaticAnswerMethod(L bots, S s) {
  for (O c : bots) try {
    S answer = callStaticAnswerMethod(c, s);
    if (!empty(answer)) ret answer;
  } catch (Throwable e) {
    print("Error calling " + getProgramID(c));
    e.printStackTrace();
  }
  ret null;
}

static S callStaticAnswerMethod(O c, S s) {
  S answer = (S) callOpt(c, "answer", s, litlist(s));
  if (answer == null)
    answer = (S) callOpt(c, "answer", s);
  return emptyToNull(answer);
}

static S callStaticAnswerMethod(S s) {
  ret callStaticAnswerMethod(mc(), s);
}

static S callStaticAnswerMethod(S s, L<S> history) {
  ret callStaticAnswerMethod(mc(), s, history);
}

static S callStaticAnswerMethod(O c, S s, L<S> history) {
  S answer = (S) callOpt(c, "answer", s, history);
  if (answer == null)
    answer = (S) callOpt(c, "answer", s);
  return emptyToNull(answer);
}