code: protected function runHelp(InputInterface $input, OutputInterface $output)
      {
          /* @var HelpCommand $help */
          $help = $this->getApplication()->find('help');
          $help->setCommand($this);
          $help->run($input, $output);
      }
docs: Runs help command
  
  @param InputInterface  $input  The InputInterface instance
  @param OutputInterface $output The OutputInterface instance
  
  @return int