code: public static Kidnummer mod11Kid(String baseNumber, int targetLength) {
          if (baseNumber.length() >= targetLength)
              throw new IllegalArgumentException("baseNumber too long");
          String padded = String.format("%0" + (targetLength-1) + "d", new BigInteger(baseNumber));
          Kidnummer k = new Kidnummer(padded + "0");
          return KidnummerValidator.getKidnummer(padded + calculateMod11CheckSum(getMod11Weights(k), k));
      }
docs: Create a valid KID numer of the wanted length, using MOD11.
  Input is padded with leading zeros to reach wanted target length
  @param baseNumber base number to calculate checksum digit for
  @param targetLength wanted length, 0-padded. Between 2-25
  @return Kidnummer