public static String unparseKeyCodes(Couple<List<Integer>> pairs) {
    StringBuilder result = new StringBuilder();

    List<Integer> codes = pairs.getFirst();
    List<Integer> modifiers = pairs.getSecond();

    for (int i = 0; i < codes.size(); i++) {
      Integer each = codes.get(i);
      result.append(each.toString());
      result.append(MODIFIER_DELIMITER);
      result.append(modifiers.get(i));
      if (i < codes.size() - 1) {
        result.append(CODE_DELIMITER);
      }
    }

    return result.toString();
  }
public static String unparseKeyCodes(Couple<List<Integer>> pairs)