docs: public ServiceCall<Classifier> updateClassifier(UpdateClassifierOptions updateClassifierOptions) {
      Validator.notNull(updateClassifierOptions, "updateClassifierOptions cannot be null");
      Validator.isTrue((updateClassifierOptions.positiveExamples() != null) || (updateClassifierOptions
          .negativeExamples() != null), "At least one of positiveExamples or negativeExamples must be supplied.");
      String[] pathSegments = { "v3/classifiers" };
      String[] pathParameters = { updateClassifierOptions.classifierId() };
      RequestBuilder builder = RequestBuilder.post(RequestBuilder.constructHttpUrl(getEndPoint(), pathSegments,
          pathParameters));
      builder.query("version", versionDate);
      Map<String, String> sdkHeaders = SdkCommon.getSdkHeaders("watson_vision_combined", "v3", "updateClassifier");
      for (Entry<String, String> header : sdkHeaders.entrySet()) {
        builder.header(header.getKey(), header.getValue());
      }
      builder.header("Accept", "application/json");
      MultipartBody.Builder multipartBuilder = new MultipartBody.Builder();
      multipartBuilder.setType(MultipartBody.FORM);
      if (updateClassifierOptions.positiveExamples() != null) {
        for (Map.Entry<String, InputStream> entry : updateClassifierOptions.positiveExamples().entrySet()) {
          String partName = String.format("%s_positive_examples", entry.getKey());
          RequestBody part = RequestUtils.inputStreamBody(entry.getValue(), "application/octet-stream");
          multipartBuilder.addFormDataPart(partName, entry.getKey(), part);
        }
      }
      if (updateClassifierOptions.negativeExamples() != null) {
        RequestBody negativeExamplesBody = RequestUtils.inputStreamBody(updateClassifierOptions.negativeExamples(),
            "application/octet-stream");
        multipartBuilder.addFormDataPart("negative_examples", updateClassifierOptions.negativeExamplesFilename(),
            negativeExamplesBody);
      }
      builder.body(multipartBuilder.build());
      return createServiceCall(builder.build(), ResponseConverterUtils.getObject(Classifier.class));
    }