docs: def add_menu(self, menu):
          """
          Adds a sub-menu to the editor context menu.
  
          Menu are put at the bottom of the context menu.
  
          .. note:: to add a menu in the middle of the context menu, you can
              always add its menuAction().
  
          :param menu: menu to add
          """
          self._menus.append(menu)
          self._menus = sorted(list(set(self._menus)), key=lambda x: x.title())
          for action in menu.actions():
              action.setShortcutContext(QtCore.Qt.WidgetShortcut)
          self.addActions(menu.actions())