code: def current_changed(self, i):
          
          m = self.model()
          ri = self.rootModelIndex()
          index = m.index(i, 0, ri)
          self.new_root.emit(index)
docs: Slot for when the current index changes.
          Emits the :data:`AbstractLevel.new_root` signal.
  
          :param index: the new current index
          :type index: int
          :returns: None
          :rtype: None
          :raises: None