code: def __getitem__(self, item):
      return self.data[item]
  
file_path: fastNLP/tests/core/dataloaders/jittor_dataloader/test_fdl.py
imports: import pytest
  import numpy
  from fastNLP.envs import _module_available
  from fastNLP.core.dataloaders.jittor_dataloader import JittorDataLoader, prepare_jittor_dataloader
  from fastNLP.core.dataset import DataSet
  from fastNLP.core.collators import Collator
  from fastNLP.io.data_bundle import DataBundle
  from fastNLP.envs.imports import _NEED_IMPORT_JITTOR
label_desc: Use image node_id 2 for calling the MyDataset obj's underlying member method code with example usage: obj.__getitem__(item) and returns: self