func (r Rule) validateExpiration() error {
	return r.Expiration.Validate()
}

func (r Rule) validateNoncurrentExpiration() error {
	return r.NoncurrentVersionExpiration.Validate()
}

func (r Rule) validatePrefixAndFilter() error {
	if !r.Prefix.set && r.Filter.IsEmpty() || r.Prefix.set && !r.Filter.IsEmpty() {
		return errXMLNotWellFormed
	}
	if !r.Prefix.set {
		return r.Filter.Validate()
	}
	return nil
}