"""
        if self.cid is not None:
            fetcher = self._create_credentials_fetcher()
            return RefreshableCredentials.create_from_metadata(
                metadata=fetcher(),
                refresh_using=fetcher,
                method=self.METHOD,
            )
        else:
            return None

    def _create_credentials_fetcher(self):
        method = self.METHOD

        def fetch_credentials():

	switch cfg.Name {
	case storageclass.STANDARD, storageclass.RRS:
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, errTierReservedName), r.URL)
		return
	}

	// Refresh from the disk in case we had missed notifications about edits from peers.
	if err := globalTierConfigMgr.Reload(ctx, objAPI); err != nil {
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
		return
	}

var errSkipFile = errors.New("skip this file")

var errIgnoreFileContrib = errors.New("ignore this file's contribution toward data-usage")

// errXLBackend XL drive mode requires fresh deployment.
var errXLBackend = errors.New("XL backend requires fresh drive")

// StorageErr represents error generated by xlStorage call.
type StorageErr string

func (h StorageErr) Error() string {
	return string(h)
}

)

type arnTarget struct {
	Client      *TargetClient
	lastRefresh time.Time
}

// arnErrs represents number of errors seen for a ARN and if update is in progress
// to refresh remote targets from bucket metadata.
type arnErrs struct {
	count            int64
	updateInProgress bool
	bucket           string
}

// BucketTargetSys represents bucket targets subsystem

          "refId": "StandardVariableQuery"
        },
        "refresh": 1,
        "regex": "",
        "skipUrlSync": false,
        "sort": 0,
        "type": "query"
      }
    ]
  },
  "time": {
    "from": "now-1h",
    "to": "now"
  },
  "timepicker": {
    "refresh_intervals": [
      "10s",
      "30s",
      "1m",
      "5m",

	// GlobalStaleUploadsCleanupInterval - Cleanup interval when the stale uploads cleanup is initiated.
	GlobalStaleUploadsCleanupInterval = time.Hour * 6 // 6 hrs.

	// Refresh interval to update in-memory iam config cache.
	globalRefreshIAMInterval = 10 * time.Minute

	// Limit of location constraint XML for unauthenticated PUT bucket operations.
	maxLocationConstraintSize = 3 * humanize.MiByte

## Configuration Directory

          "refId": "StandardVariableQuery"
        },
        "refresh": 1,
        "regex": "",
        "skipUrlSync": false,
        "sort": 0,
        "type": "query"
      }
    ]
  },
  "time": {
    "from": "now-6h",
    "to": "now"
  },
  "timepicker": {
    "refresh_intervals": [
      "10s",
      "30s",
      "1m",
      "5m",

				iamLogIf(ctx, fmt.Errorf("Failure in periodic refresh for IAM (took %.2fs): %v", time.Since(refreshStart).Seconds(), err), logger.WarningKind)
			} else {
				took := time.Since(refreshStart).Seconds()
				if took > maxDurationSecondsForLog {
					// Log if we took a lot of time to load.
					logger.Info("IAM refresh took %.2fs", took)
				}
			}

			// Purge expired STS credentials.

	}

	// Fill all the necessary metadata.
	// Update `xl.meta` content on each disks.
	for index := range partsMetadata {
		partsMetadata[index].Size = n
		partsMetadata[index].Fresh = true
		partsMetadata[index].ModTime = modTime
		partsMetadata[index].Metadata = opts.UserDefined
	}

	// Set an additional header when data is inlined.
	for index := range partsMetadata {