code: @Override
    public TransferReversal update(Map<String, Object> params, RequestOptions options)
        throws StripeException {
      String url;
      if (this.getTransfer() != null) {
        url =
            String.format(
                "%s%s",
                Stripe.getApiBase(),
                String.format(
                    "/v1/transfers/%s/reversals/%s",
                    ApiResource.urlEncodeId(this.getTransfer()),
                    ApiResource.urlEncodeId(this.getId())));
      } else {
        throw new InvalidRequestException(
            "Unable to construct url because [transfer] field(s) are all null",
            null,
            null,
            null,
            0,
            null);
      }
      return request(ApiResource.RequestMethod.POST, url, params, TransferReversal.class, options);
    }
docs: Updates the specified reversal by setting the values of the parameters passed. Any parameters
  not provided will be left unchanged.
  
  <p>This request only accepts metadata and description as arguments.