docs: def _check_cmd(call):
      '''
      Check the output of the cmd.run_all function call.
      '''
      if call['retcode'] != 0:
          comment = ''
          std_err = call.get('stderr')
          std_out = call.get('stdout')
          if std_err:
              comment += std_err
          if std_out:
              comment += std_out
  
          raise CommandExecutionError('Error running command: {0}'.format(comment))
  
      return call