code: public function setTranslator(TranslatorInterface $oTranslator = null, $sTextDomain = null)
      {
          $this->translator = $oTranslator;
          if (null !== $sTextDomain) {
              $this->setTranslatorTextDomain($sTextDomain);
          }
          return $this;
      }
docs: Sets translator to use in helper
  @see TranslatorAwareInterface::setTranslator()
  @param TranslatorInterface $oTranslator : [optional] translator. Default is null, which sets no translator.
  @param string $sTextDomain : [optional] text domain Default is null, which skips setTranslatorTextDomain
  @return TwbBundleFormElement