code: public ServiceCall<Voices> listVoices(ListVoicesOptions listVoicesOptions) {
      String[] pathSegments = { "v1/voices" };
      RequestBuilder builder = RequestBuilder.get(RequestBuilder.constructHttpUrl(getEndPoint(), pathSegments));
      Map<String, String> sdkHeaders = SdkCommon.getSdkHeaders("text_to_speech", "v1", "listVoices");
      for (Entry<String, String> header : sdkHeaders.entrySet()) {
        builder.header(header.getKey(), header.getValue());
      }
      builder.header("Accept", "application/json");
      if (listVoicesOptions != null) {
      }
      return createServiceCall(builder.build(), ResponseConverterUtils.getObject(Voices.class));
    }
docs: List voices.
  
  Lists all voices available for use with the service. The information includes the name, language, gender, and other
  details about the voice. To see information about a specific voice, use the **Get a voice** method.
  
  **See also:** [Listing all available
  voices](https://cloud.ibm.com/docs/services/text-to-speech/voices.html#listVoices).
  
  @param listVoicesOptions the {@link ListVoicesOptions} containing the options for the call
  @return a {@link ServiceCall} with a response type of {@link Voices}