code: private static int parseAreaCode(String areaCode) {
  
      String normalized = areaCode;
      if (normalized.startsWith("(0)")) {
        normalized = normalized.substring(3);
      } else if (normalized.startsWith("(1)")) {
        normalized = normalized.substring(3);
      } else if (normalized.startsWith("0")) {
        normalized = normalized.substring(1);
      }
      if (normalized.startsWith("0")) {
        throw new IllegalArgumentException(areaCode);
      }
      try {
        int ac = Integer.parseInt(normalized);
        return ac;
      } catch (NumberFormatException e) {
        throw new IllegalArgumentException(areaCode, e);
      }
    }
docs: This method parses a {@link AreaCode} given as {@link String} to its {@link #getAreaCode() int representation}.
  
  @param areaCode is the {@link AreaCode} as {@link String}.
  @return the {@link AreaCode} as int.