Symfony\Component\Console\Application::getDefaultHelperSet PHP Method

    protected function getDefaultHelperSet()
    {
        return new HelperSet(array(new FormatterHelper(), new DebugFormatterHelper(), new ProcessHelper(), new QuestionHelper()));
    }

 /**
  * {@inheritdoc}
  */
 protected function getDefaultHelperSet()
 {
     $helperSet = parent::getDefaultHelperSet();
     $helperSet->set(new Config());
     $helperSet->set(new YoHelper());
     return $helperSet;
 }