code: def move(self, item, parent, index):
          
          self._visual_drag.move(item, parent, index)
          ttk.Treeview.move(self, item, parent, index)
docs: Moves item to position index in parent’s list of children.
  
          It is illegal to move an item under one of its descendants. If index is
          less than or equal to zero, item is moved to the beginning, if greater
          than or equal to the number of children, it is moved to the end.
          If item was detached it is reattached.
  
          :param item: item's identifier
          :type item: str
          :param parent: new parent of item
          :type parent: str
          :param index: where in the list of parent’s children to insert item
          :type index: int of "end"