code: def __getitem__(self, idx):
      dataset_idx = self.dataset_index[idx]
      sample_idx = self.dataset_sample_index[idx]
      return self.datasets[dataset_idx][sample_idx]
  
file_path: colossalai/examples/tutorial/sequence_parallel/data/datasets/blendable_dataset.py
imports: import time
  import numpy
  import torch
label_desc: Use image node_id 3 for calling the BlendableDataset obj's underlying member method code with example usage: obj.__getitem__(idx) and returns: self