private void checkGuessAndFeedbackMatch(List<String> guessHistory, List<String> feedbackHistory,
      String code){
    check(guessHistory.size() == feedbackHistory.size(),"hisotry size mismatch",guessHistory,
        feedbackHistory);
    Iterator<String> git = guessHistory.iterator();
    Iterator<String> fit = feedbackHistory.iterator();
    while (git.hasNext() || fit.hasNext()){
      String g = git.next();
      String f = fit.next();
      String gf = CodeFeedback.getValidFeedback(code,g);
      check(gf.equals(f),"hacked feedback",g,f,gf);
    }
  }