checkHashCode(Sets.cartesianProduct(set(1, num), set(2, num - 1)));
    checkHashCode(Sets.cartesianProduct(set(1, num), set(2, num - 1), set(3, num + 1)));

    // a bigger one
    checkHashCode(
        Sets.cartesianProduct(set(1, num, num + 1), set(2), set(3, num + 2), set(4, 5, 6, 7, 8)));
  }

  public void testPowerSetEmpty() {

          "nesec--nx??at?b?c!cul??dv?i&blo&-oipmet?oipmet??cserb?drabmol?g&gof?urep??l&gup?i&cis?me&-oigger?oigger???uig&-&aizenev&-iluirf?iluirf??ev&-iluirf?iluirf??v&-iluirf?iluirf???aizenev&-iluirf?iluirf??ev&-iluirf?iluirf??v&-iluirf?iluirf????n&a&brev?cul?pmac?tac??idras?obrac&-saiselgi?saiselgi??resi??otsip?r&b&alac!-oigger?oigger??mu??dna&-&attelrab-inart?inart-attelrab??attelrabinart?inartattelrab?ssela??epmi?ugil??tnelav&-obiv?obiv??vap?z&e&nev?ps&-al?al???...

	RangeRequested   string `xml:"RangeRequested,omitempty" json:"RangeRequested,omitempty"`
}

// APIErrorCode type of error status.
type APIErrorCode int

//go:generate stringer -type=APIErrorCode -trimprefix=Err $GOFILE

// Error codes, non exhaustive list - http://docs.aws.amazon.com/AmazonS3/latest/API/ErrorResponses.html
const (
	ErrNone APIErrorCode = iota
	ErrAccessDenied
	ErrBadDigest

var (
	// XL header specifies the format
	xlHeader = [4]byte{'X', 'L', '2', ' '}

	// Current version being written.
	xlVersionCurrent [4]byte
)

//go:generate msgp -file=$GOFILE -unexported
//go:generate stringer -type VersionType,ErasureAlgo -output=xl-storage-format-v2_string.go $GOFILE

const (
	// Breaking changes.
	// Newer versions cannot be read by older software.
	// This will prevent downgrades to incompatible versions.

							versionID: fi.VersionID,
							queued:    time.Now(),
							setIndex:  er.setIndex,
							poolIndex: er.poolIndex,
							scanMode:  scan,
						})
					})
					// Healing is triggered and we have written
					// successfully the content to client for
					// the specific part, we should `nil` this error
					// and proceed forward, instead of throwing errors.
					err = nil
				}
			}

	case osIsNotExist(err):
		err = errDiskNotFound
	case isSysErrTooLong(err):
		err = errFileNameTooLong
	case isSysErrIO(err):
		err = errFaultyDisk
	}

	return di, err
}

// Implements stringer compatible interface.
func (s *xlStorage) String() string {
	return s.drivePath
}

func (s *xlStorage) Hostname() string {
	return s.endpoint.Host
}

func (s *xlStorage) Endpoint() Endpoint {

	total := uint64(0)
	for _, z := range p {
		total += z.Available
	}
	return total
}

// FilterMaxUsed will filter out any pools that has used percent bigger than max,
// unless all have that, in which case all are preserved.
func (p serverPoolsAvailableSpace) FilterMaxUsed(max int) {
	// We aren't modifying p, only entries in it, so we don't need to receive a pointer.