docs: def get_one_time_boot(self):
          """Retrieves the current setting for the one time boot.
  
          :returns: Returns the first boot device that would be used in next
                   boot. Returns 'Normal' is no device is set.
          :raises: IloError, on an error from iLO.
          :raises: IloCommandNotSupportedError, if the command is not supported
                   on the server.
          """
          system = self._get_host_details()
          try:
              if system['Boot']['BootSourceOverrideEnabled'] == 'Once':
                  device = system['Boot']['BootSourceOverrideTarget']
                  if device in DEVICE_RIS_TO_COMMON:
                      return DEVICE_RIS_TO_COMMON[device]
                  return device
              else:
                  # value returned by RIBCL if one-time boot setting are absent
                  return 'Normal'
  
          except KeyError as e:
              msg = "get_one_time_boot failed with the KeyError:%s"
              raise exception.IloError((msg) % e)