code: def create_treeitem(self, ):
          
          p = self.get_parent()
          root = self.get_root()
          if p:
              pitem = p.get_treeitem()
          else:
              pitem = root.get_rootitem()
          idata = root.create_itemdata(self)
          item = TreeItem(idata, parent=pitem)
          return item
docs: Create a new treeitem for this reftrack instance.
  
          .. Note:: Parent should be set, Parent should already have a treeitem.
                    If there is no parent, the root tree item is used as parent for the treeitem.
  
          :returns: a new treeitem that contains a itemdata with the reftrack instanec.
          :rtype: :class:`TreeItem`
          :raises: None