code: def __getitem__(self, item):
      return self._data[item]
  
file_path: fastNLP/tests/helpers/datasets/jittor_data.py
imports: from fastNLP.envs.imports import _NEED_IMPORT_JITTOR
label_desc: Use image node_id 2 for calling the JittorNormalDataset obj's underlying member method code with example usage: obj.__getitem__(item) and returns: self