ap := r.Message.(*v1beta1.AuthorizationPolicy)

	for i, rule := range ap.Rules {
		for j, from := range rule.From {
			for k, ns := range append(from.Source.Namespaces, from.Source.NotNamespaces...) {
				if !matchNamespace(ns, c) {
					m := msg.NewReferencedResourceNotFound(r, "namespace", ns)

					nsIndex := k
					if nsIndex >= len(from.Source.Namespaces) {
						nsIndex -= len(from.Source.Namespaces)
					}

	if !ok {
		return nil, nil, fmt.Errorf("not a namespace")
	}
	return labels.Set(namespaceObj.Labels), NamespaceToSelectableFields(namespaceObj), nil
}

// MatchNamespace returns a generic matcher for a given label and field selector.
func MatchNamespace(label labels.Selector, field fields.Selector) apistorage.SelectionPredicate {
	return apistorage.SelectionPredicate{
		Label:    label,
		Field:    field,
		GetAttrs: GetAttrs,

		NewFunc:                   func() runtime.Object { return &api.Namespace{} },
		NewListFunc:               func() runtime.Object { return &api.NamespaceList{} },
		PredicateFunc:             namespace.MatchNamespace,
		DefaultQualifiedResource:  api.Resource("namespaces"),
		SingularQualifiedResource: api.Resource("namespace"),

		CreateStrategy:      namespace.Strategy,
		UpdateStrategy:      namespace.Strategy,