How to use the pgl.graph_kernel.node2vec_sample function in pgl

if np.any(mask):
                cur_walk_ids = cur_walk_ids[mask]
                cur_nodes = cur_nodes[mask]
                prev_nodes = prev_nodes[mask]
                prev_succs = prev_succs[mask]
            else:
                # stop when all nodes have no successor
                break
            cur_succs = self.successor(cur_nodes)
            num_nodes = cur_nodes.shape[0]
            nxt_nodes = np.zeros(num_nodes, dtype="int64")

            for idx, (succ, prev_succ, walk_id, prev_node) in enumerate(
                    zip(cur_succs, prev_succs, cur_walk_ids, prev_nodes)):

                sampled_succ = graph_kernel.node2vec_sample(succ, prev_succ,
                                                            prev_node, p, q)
                walk[walk_id].append(sampled_succ)
                nxt_nodes[idx] = sampled_succ

            prev_nodes, prev_succs = cur_nodes, cur_succs
            cur_nodes = nxt_nodes
        return walk

cur_walk_ids = cur_walk_ids[mask]
            cur_nodes = cur_nodes[mask]
            prev_nodes = prev_nodes[mask]
            prev_succs = prev_succs[mask]
            cur_succs = cur_succs[mask]
        else:
            # stop when all nodes have no successor
            break
        num_nodes = cur_nodes.shape[0]
        nxt_nodes = np.zeros(num_nodes, dtype="int64")

        for idx, (
                succ, prev_succ, walk_id, prev_node
        ) in enumerate(zip(cur_succs, prev_succs, cur_walk_ids, prev_nodes)):

            sampled_succ = graph_kernel.node2vec_sample(succ, prev_succ,
                                                        prev_node, p, q)
            walk[walk_id].append(sampled_succ)
            nxt_nodes[idx] = sampled_succ

        prev_nodes, prev_succs = cur_nodes, cur_succs
        cur_nodes = nxt_nodes
    return walk