How to use the pgl.redis_graph.RedisGraph function in pgl

def work():
        """work
        """
        redis_configs = [{
            "host": socket.gethostbyname(socket.gethostname()),
            "port": 7430
        }, ]
        graph = redis_graph.RedisGraph("sub_graph", redis_configs, 64)
        first = True
        for batch_train_samples, batch_train_labels in batch_info:
            start_nodes = batch_train_samples
            nodes = start_nodes
            eids = []
            eid2edges = {}
            for max_deg in samples:
                pred, pred_eid = graph.sample_predecessor(
                    start_nodes, max_degree=max_deg, return_eids=True)
                for _dst, _srcs, _eids in zip(start_nodes, pred, pred_eid):
                    for _src, _eid in zip(_srcs, _eids):
                        eid2edges[_eid] = (_src, _dst)

                last_nodes = nodes
                nodes = [nodes, pred]
                eids = [eids, pred_eid]