func (a *Attributes) MatchOnlyVersion(attr *Attributes) bool {
	if a == nil || attr == nil {
		return a == attr  
	}
	return matchAttr(a.Version, attr.Version)
}
MatchOnlyVersion checks whether version matches
package wfn
type Matcher interface {
	Match(attrs []*Attributes, requireVersion bool) (matches []*Attributes)
	Config() []*Attributes
}
func (a *Attributes) Config() []*Attributes {
	return []*Attributes{a}
}