@Override
    public TranslateFactory getDefaultServiceFactory() {
      return DefaultTranslateFactory.INSTANCE;
    }
Sets the code for the default target language. If not set, English ({@code en}) is used.
Calls to {@link Translate#translate(List, TranslateOption...)} and {@link
Translate#translate(String, TranslateOption...)} will use this value unless an option from
{@link TranslateOption#targetLanguage(String)} is explicitly provided.

@return the builder
java-translate/google-cloud-translate/src/main/java/com/google/cloud/translate/TranslateOptions.java