def METHOD_NAME(self, label):
    """Add a new submenu in the current menu."""
    # add an item
    item = self.add_item(label, menu=True)
    if self.parent is None:
        # create a SPAN for the submenu
        span = html.SPAN(Class="brython-menu-submenu")
        span.style.position = "absolute"
    return Menu(self.container, item, default_css=self.default_css)