"istio-injection":            "enabled",
		}),
	}

	client := kube.NewFakeClient(nss...)
	expected := sets.New[string]("default", "no-ambient")
	actual, err := getNamespaces(context.TODO(), client, "istio-system")
	assert.NoError(t, err)
	for _, ns := range actual {
		assert.Equal(t, true, expected.Contains(ns.Name))
	}

}

func ipstr(ipv6 bool) string {
	if ipv6 {
		return "ipv6"
	}
	return "ipv4"
}

func compareToGolden(t *testing.T, ipv6 bool, name string, actual []string) {
	t.Helper()
	gotBytes := []byte(strings.Join(actual, "\n"))
	goldenFile := filepath.Join("testdata", name+".golden")
	if ipv6 {
		goldenFile = filepath.Join("testdata", name+"_ipv6.golden")
	}

The only new thing is the `callbacks=invoices_callback_router.routes` as an argument to the *path operation decorator*. We'll see what that is next.

## Documenting the callback

The actual callback code will depend heavily on your own API app.

And it will probably vary a lot from one app to the next.

It could be just one or two lines of code, like:

```Python

This is because it is expected that **your users** would define the actual **URL path** where they want to receive the webhook request in some other way (e.g. a web dashboard).

### Check the docs