code: public Order cancelOrder(String orderId, String variety) throws KiteException, JSONException, IOException {
          String url = routes.get("orders.cancel").replace(":variety", variety).replace(":order_id", orderId);
          Map<String, Object> params = new HashMap<String, Object>();
  
          JSONObject jsonObject = new KiteRequestHandler(proxy).deleteRequest(url, params, apiKey, accessToken);
          Order order =  new Order();
          order.orderId = jsonObject.getJSONObject("data").getString("order_id");
          return order;
      }
docs: Cancels an order.
  @param orderId order id of the order to be cancelled.
  @param variety [variety="regular"]. Order variety can be bo, co, amo, regular.
  @return Order object contains only orderId.
  @throws KiteException is thrown for all Kite trade related errors.
  @throws JSONException is thrown when there is exception while parsing response.
  @throws IOException is thrown when there is connection error.