code: private boolean checkLuVatId(final String pvatId) {
      final int numberPart = Integer.parseInt(pvatId.substring(2, 8));
      final int checkSum = Integer.parseInt(pvatId.substring(8));
      final int calculatedCheckSum = numberPart % 89;
      return checkSum == calculatedCheckSum;
    }
docs: check the VAT identification number, country version for Luxembourg.
  
  @param pvatId vat id to check
  @return true if checksum is ok