code: public Observable<ServiceResponse<AppServiceCertificateOrderInner>> createOrUpdateWithServiceResponseAsync(String resourceGroupName, String certificateOrderName, AppServiceCertificateOrderInner certificateDistinguishedName) {
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (certificateOrderName == null) {
              throw new IllegalArgumentException("Parameter certificateOrderName is required and cannot be null.");
          }
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (certificateDistinguishedName == null) {
              throw new IllegalArgumentException("Parameter certificateDistinguishedName is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          Validator.validate(certificateDistinguishedName);
          Observable<Response<ResponseBody>> observable = service.createOrUpdate(resourceGroupName, certificateOrderName, this.client.subscriptionId(), certificateDistinguishedName, this.client.apiVersion(), this.client.acceptLanguage(), this.client.userAgent());
          return client.getAzureClient().getPutOrPatchResultAsync(observable, new TypeToken<AppServiceCertificateOrderInner>() { }.getType());
      }
docs: Create or update a certificate purchase order.
  Create or update a certificate purchase order.
  
  @param resourceGroupName Name of the resource group to which the resource belongs.
  @param certificateOrderName Name of the certificate order.
  @param certificateDistinguishedName Distinguished name to to use for the certificate order.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request