public class ZipCode {

  public static String from(String zipCode) {
    if (zipCode.length() != 5) {
      throw new InvalidZipCodeException();
    }
    try {
      int parsedZip = Integer.parseInt(zipCode);
    } catch (NumberFormatException numberException) {
      throw new InvalidZipCodeException();
    }
    return zipCode;
  }