code: def create_widget(self):
          
          d = self.declaration
          Snackbar.make(self.parent_widget(), d.text,
                        0 if d.duration else -2).then(self.on_widget_created)
docs: Create the underlying widget.
  
          A toast is not a subclass of view, hence we don't set name as widget
          or children will try to use it as their parent (which crashes).