code: protected function execute(InputInterface $input, OutputInterface $output)
      {
          try {
              $this->doPreExecute($input, $output);
              $this->returnCode = $this->doExecute($input, $output);
              $this->doPostExecute($input, $output);
          } catch(Exception $e) {
              $this->returnCode = static::RETURN_ERROR;
              throw $e;
          }
  
          return $this->returnCode;
      }
docs: Execute command.
  
  @param InputInterface $input
  Input.
  @param OutputInterface $output
  Output.
  
  @return int
  Return Code.