private static boolean areNumbersEquivalent(RegExpNumber number1, RegExpNumber number2) {
    if (number1 == null) {
      return number2 == null;
    }
    else if (number2 == null) {
      return false;
    }
    final Number value1 = number1.getValue();
    final Number value2 = number2.getValue();
    return value1 != null && value1.equals(value2);
  }
private static boolean areNumbersEquivalent(RegExpNumber number1, RegExpNumber number2)