code: def currentChanged(self, current, prev):
          
          m = self.model()
          p = current.parent()
          index = m.index(current.row(), 0, p)
          self.new_root.emit(index)
          return super(ListLevel, self).currentChanged(current, prev)
docs: Slot for when the current index changes.
          Emits the :data:`AbstractLevel.new_root` signal.
  
          :param current: the new current index
          :type current: QtGui.QModelIndex
          :param current: the previous current index
          :type current: QtGui.QModelIndex
          :returns: None
          :rtype: None
          :raises: None