def save(self):
        """save the graph list and the labels"""
        labels = {}
        for i, label in enumerate(self.labels):
            labels["{}".format(i)] = F.tensor(label)
        save_graphs(str(self.graph_path), self.graphs, labels)
        if self.verbose:
            print("Done saving data into cached files.")
save the graph list and the labels
python/dgl/data/citation_graph.py