code: @Override
      public OutputSpeech getOutputSpeech() {
          if (outputSpeech != null) {
              return outputSpeech;
          }
  
          final String utterance;
  
          try {
              utterance = yamlReader.getRandomUtterance(output).orElseThrow(IOException::new);
              LOG.debug("Random utterance read out from YAML file: " + utterance);
          } catch (IOException e) {
              LOG.error("Error while generating response utterance.", e);
              return null;
          }
  
          final String utteranceSsml = resolveSlotsInUtterance(utterance);
  
          final SsmlOutputSpeech ssmlOutputSpeech = new SsmlOutputSpeech();
          ssmlOutputSpeech.setSsml(utteranceSsml);
          return ssmlOutputSpeech;
      }
docs: Gets the generated output speech.
  @return the generated output speech.