code: def __len__(self):
      return self.data_feature.shape[0]
  
file_path: BigDL/python/chronos/src/bigdl/chronos/simulator/doppelganger/data_module.py
imports: import os
  import pickle
  import numpy
  import sys
  import torch
  from torch.utils.data import DataLoader, Dataset
  from pytorch_lightning import LightningDataModule
  from .util import add_gen_flag, normalize_per_sample, renormalize_per_sample
label_desc: Use image node_id 2 for calling the CustomizedDataset obj's underlying member method code with example usage: obj.__len__() and returns: self