return &equivalentResourceRegistry{}
}

// NewEquivalentResourceRegistryWithIdentity creates a resource mapper with a custom identity function.
// If "" is returned by the function, GroupResource#String is used as the identity.
// GroupResources with the same identity string are considered equivalent.
func NewEquivalentResourceRegistryWithIdentity(keyFunc func(schema.GroupResource) string) EquivalentResourceRegistry {

	a := &Matcher{namespaceMatcher: &namespace.Matcher{}, objectMatcher: &object.Matcher{}}

	allScopes := v1.AllScopes
	exactMatch := v1.Exact
	equivalentMatch := v1.Equivalent

	mapper := runtime.NewEquivalentResourceRegistryWithIdentity(func(resource schema.GroupResource) string {
		if resource.Resource == "deployments" {
			// co-locate deployments in all API groups
			return "/deployments"
		}
		return ""
	})

		namespaceMatcher: &namespace.Matcher{},
		objectMatcher:    &object.Matcher{},
	}

	allScopes := v1.AllScopes
	exactMatch := v1.Exact
	equivalentMatch := v1.Equivalent

	mapper := runtime.NewEquivalentResourceRegistryWithIdentity(func(resource schema.GroupResource) string {
		if resource.Resource == "deployments" {
			// co-locate deployments in all API groups
			return "/deployments"
		}
		return ""
	})

		},
	}

	for _, tc := range testcases {
		t.Run(tc.Name, func(t *testing.T) {
			mapper := NewEquivalentResourceRegistryWithIdentity(tc.IdentityFunc)

			// register
			for _, data := range kindsToRegister {
				mapper.RegisterKindFor(data.gvr, data.subresource, data.gvk)
			}
			// verify

	if c.EquivalentResourceRegistry == nil {
		if c.RESTOptionsGetter == nil {
			c.EquivalentResourceRegistry = runtime.NewEquivalentResourceRegistry()
		} else {
			c.EquivalentResourceRegistry = runtime.NewEquivalentResourceRegistryWithIdentity(func(groupResource schema.GroupResource) string {
				// use the storage prefix as the key if possible
				if opts, err := c.RESTOptionsGetter.GetRESTOptions(groupResource); err == nil {