// ref: https://docs.aws.amazon.com/AmazonS3/latest/API/API_LifecycleRuleAndOperator.html
	// i.e, predCount >= 2
	var predCount int
	if a.Prefix.set {
		predCount++
	}
	predCount += len(a.Tags)
	if a.ObjectSizeGreaterThan > 0 {
		predCount++
	}
	if a.ObjectSizeLessThan > 0 {
		predCount++
	}

	if predCount < 2 {
		return errXMLNotWellFormed
	}

	if a.ContainsDuplicateTag() {
		return errDuplicateTagKey

		tagPred
		sizeLtPred
		sizeGtPred
	)
	var predCount int
	var pType predType
	if !f.And.isEmpty() {
		pType = andPred
		predCount++
	}
	if f.Prefix.set {
		pType = prefixPred
		predCount++
	}
	if !f.Tag.IsEmpty() {
		pType = tagPred
		predCount++
	}
	if f.ObjectSizeGreaterThan != 0 {
		pType = sizeGtPred
		predCount++
	}
	if f.ObjectSizeLessThan != 0 {