code: def __getitem__(self, idx):
      return self._transform(self.dataset[idx])
  
imports: import time
  import unittest
  import json
  import os
  import random
  from pgl.utils.data.dataset import Dataset, StreamDataset
  from pgl.utils.data.dataloader import Dataloader
label_desc: Use image node_id 2 for calling the ListDataset obj's underlying member method code with example usage: obj.__getitem__(idx) and returns: self