docs: def do_startup(self):
          """Gtk.Application.run() will call this function()"""
  
          Gtk.Application.do_startup(self)
          gtk_window = Gtk.ApplicationWindow(application=self)
          gtk_window.set_title('AppKit')
          webkit_web_view = WebKit.WebView()
          webkit_web_view.load_uri('http://localhost:' + str(self.port))
  
          screen = Gdk.Screen.get_default()
          monitor_geometry = screen.get_primary_monitor()
          monitor_geometry = screen.get_monitor_geometry(monitor_geometry)
  
          settings = webkit_web_view.get_settings()
          settings.set_property('enable-universal-access-from-file-uris', True)
          settings.set_property('enable-file-access-from-file-uris', True)
          settings.set_property('default-encoding', 'utf-8')
          gtk_window.set_default_size(
              monitor_geometry.width * 1.0 / 2.0,
              monitor_geometry.height * 3.0 / 5.0,
          )
          scrollWindow = Gtk.ScrolledWindow()
          scrollWindow.add(webkit_web_view)
          gtk_window.add(scrollWindow)
          gtk_window.connect('delete-event', self._on_gtk_window_destroy)
          webkit_web_view.connect('notify::title', self._on_notify_title)
          self.gtk_window = gtk_window
          self.webkit_web_view = webkit_web_view
          gtk_window.show_all()