code: def remove(self, index):
          
          data = self.data
          index = self._split(index)
          for j, c in enumerate(index):
              i = int(c) - 1
              if j + 1 == len(index):
                  try:
                      del data[i]
                  except IndexError:
                      raise NoItemError('.'.join(index))
              else:
                  data = data[i][4]
docs: Removes specified item from the model.
  
          :index: Should have a form "<itemref>.<subitemref...>" (e.g. "1.1").
  
          :index: Item's index.