code: def __getitem__(self, index):
      return tuple(d[index] for d in self.lists_of_data)
  
file_path: dgl/examples/pytorch/rrn/sudoku_data.py
imports: import csv
  import os
  import urllib.request
  import zipfile
  from copy import copy
  import dgl
  import numpy
  import torch
  from torch.utils.data import DataLoader, RandomSampler, SequentialSampler
  from torch.utils.data.dataset import Dataset
label_desc: Use image node_id 2 for calling the ListDataset obj's underlying member method code with example usage: obj.__getitem__(index) and returns: tuple