// greater than zero
func (eDays *ExpirationDays) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
	var numDays int
	err := d.DecodeElement(&numDays, &startElement)
	if err != nil {
		return err
	}
	if numDays <= 0 {
		return errLifecycleInvalidDays
	}
	*eDays = ExpirationDays(numDays)
	return nil
}

// MarshalXML encodes number of days to expire if it is non-zero and
// encodes empty string otherwise

    for (int i = 1; i < numKeys; i++) {
      nodes.get(i).checkAcquiredLocks(Policies.THROW, nodes.subList(0, i));
    }
    // Pre-populate all disallowedPriorLocks with nodes of larger ordinal.
    for (int i = 0; i < numKeys - 1; i++) {
      nodes.get(i).checkAcquiredLocks(Policies.DISABLED, nodes.subList(i + 1, numKeys));
    }
    return Collections.unmodifiableMap(map);
  }