code: def get_iter(self, path):
          
  
          path = self._coerce_path(path)
          success, aiter = super(TreeModel, self).get_iter(path)
          if not success:
              raise ValueError("invalid tree path '%s'" % path)
          return aiter
docs: :param path: the :obj:`Gtk.TreePath`-struct
          :type path: :obj:`Gtk.TreePath`
  
          :raises: :class:`ValueError` if `path` doesn't exist
          :returns: a :obj:`Gtk.TreeIter`
          :rtype: :obj:`Gtk.TreeIter`
  
          Returns an iterator pointing to `path`. If `path` does not exist
          :class:`ValueError` is raised.