def on_iter_next(self, rowref):
        n = self.on_get_path(rowref)
        try:
            rowref = self._model_data[n+1]
        except __HOLE__, msg:
            rowref = None
        return rowref
dataset/ETHPy150Open anandology/pyjamas/pygtkweb/demos/071-generictreemodel.py/MyTreeModel.on_iter_next