I can not find information or examples about "Gtk.Application" in Genie.

What is the correct way of using the Gtk.Application class in Genie?

Good day and thank you

EDIT: I do not know if this is the best way to do it, but my code is this:

```
// compila con valac --pkg gtk+-3.0 nombre_archivo.gs
uses Gtk

class MyApplication : Gtk.Application   
    def override activate ()        
        var window = new Gtk.ApplicationWindow (this)
        window.title = "Welcome to GNOME"
        window.set_default_size (400, 400)
        window.show ()

init
    new MyApplication ().run (args)

```