}

var timeSentinel = time.Unix(0, 0).UTC()

// ErrInvalidDuration invalid token expiry
var ErrInvalidDuration = errors.New("invalid token expiry")

// ExpToInt64 - convert input interface value to int64.
func ExpToInt64(expI interface{}) (expAt int64, err error) {
	switch exp := expI.(type) {
	case string:
		expAt, err = strconv.ParseInt(exp, 10, 64)
	case float64: