docs: def set_host_power(self, target_value):
          """Sets the power state of the system.
  
          :param target_value: The target value to be set. Value can be:
              'ON' or 'OFF'.
          :raises: IloError, on an error from iLO.
          :raises: InvalidInputError, if the target value is not
              allowed.
          """
          if target_value not in POWER_RESET_MAP:
              msg = ('The parameter "%(parameter)s" value "%(target_value)s" is '
                     'invalid. Valid values are: %(valid_power_values)s' %
                     {'parameter': 'target_value', 'target_value': target_value,
                      'valid_power_values': POWER_RESET_MAP.keys()})
              raise exception.InvalidInputError(msg)
  
          # Check current power status, do not act if it's in requested state.
          current_power_status = self.get_host_power_status()
          if current_power_status == target_value:
              LOG.debug(self._("Node is already in '%(target_value)s' power "
                               "state."), {'target_value': target_value})
              return
  
          sushy_system = self._get_sushy_system(PROLIANT_SYSTEM_ID)
          try:
              sushy_system.reset_system(POWER_RESET_MAP[target_value])
          except sushy.exceptions.SushyError as e:
              msg = (self._('The Redfish controller failed to set power state '
                            'of server to %(target_value)s. Error %(error)s') %
                     {'target_value': target_value, 'error': str(e)})
              LOG.debug(msg)
              raise exception.IloError(msg)