docs: @Override
      public Response delete(String CorpNum, MgtKeyType KeyType, String MgtKey,
                             String UserID) throws PopbillException {
          if (KeyType == null)
              throw new PopbillException(-99999999, "관리번호형태가 입력되지 않았습니다.");
          if (MgtKey == null || MgtKey.isEmpty())
              throw new PopbillException(-99999999, "관리번호가 입력되지 않았습니다.");
  
          return httppost("/Taxinvoice/" + KeyType.name() + "/" + MgtKey,
                  CorpNum, null, UserID, "DELETE", Response.class);
      }