    def _get_data(self):
        """
        Get dag info from DAG.
        """
        nodes = self._dag.nodes
        edges = self._dag.edges
        dag_dict = self._dag.dag_dict
        return [[
            nodes[k].name + '(' + dag_dict[k]['iter_info']['type'] + ')',
            [i[0] + ' (' + i[1].name[0] + ')' for i in edges[nodes[k].in_edges[0]]['data'] if i[0] in nodes[k].inputs],
            [i[0] + ' (' + i[1].name[0] + ')' for i in edges[nodes[k].out_edges[0]]['data'] if i[0] in nodes[k].outputs],
            [i[0] + ' (' + i[1].name[0] + ')' for i in edges[nodes[k].in_edges[0]]['data']],
            [i[0] + ' (' + i[1].name[0] + ')' for i in edges[nodes[k].out_edges[0]]['data']],
            None if not dag_dict[k]['next_nodes'] else [nodes[i].name for i in dag_dict[k]['next_nodes']],
            dag_dict[k]['iter_info']['param']
        ] for k in self._dag.top_sort]
Get dag info from DAG.
towhee/tools/graph_visualizer.py