docs: public ServiceCall<Void> updateVoiceModel(UpdateVoiceModelOptions updateVoiceModelOptions) {
      Validator.notNull(updateVoiceModelOptions, "updateVoiceModelOptions cannot be null");
      String[] pathSegments = { "v1/customizations" };
      String[] pathParameters = { updateVoiceModelOptions.customizationId() };
      RequestBuilder builder = RequestBuilder.post(RequestBuilder.constructHttpUrl(getEndPoint(), pathSegments,
          pathParameters));
      Map<String, String> sdkHeaders = SdkCommon.getSdkHeaders("text_to_speech", "v1", "updateVoiceModel");
      for (Entry<String, String> header : sdkHeaders.entrySet()) {
        builder.header(header.getKey(), header.getValue());
      }
      builder.header("Accept", "application/json");
      final JsonObject contentJson = new JsonObject();
      if (updateVoiceModelOptions.name() != null) {
        contentJson.addProperty("name", updateVoiceModelOptions.name());
      }
      if (updateVoiceModelOptions.description() != null) {
        contentJson.addProperty("description", updateVoiceModelOptions.description());
      }
      if (updateVoiceModelOptions.words() != null) {
        contentJson.add("words", GsonSingleton.getGson().toJsonTree(updateVoiceModelOptions.words()));
      }
      builder.bodyJson(contentJson);
      return createServiceCall(builder.build(), ResponseConverterUtils.getVoid());
    }