code: def __getitem__(self, idx):
      return self.data[idx]
  
file_path: LightGBM/examples/python-guide/dataset_from_multi_hdf5.py
imports: from pathlib import Path
  import h5py
  import numpy
  import pandas
  import lightgbm
label_desc: Use image node_id 2 for calling the HDFSequence obj's underlying member method code with example usage: obj.__getitem__(idx) and returns: self