code: def __len__(self):
      return self.length
  
file_path: BigDL/python/nano/src/bigdl/nano/utils/pytorch/dataset.py
imports: import torch
  from torch.utils.data import Dataset
  from torch.utils.data.dataloader import default_collate
label_desc: Use image node_id 2 for calling the RepeatDataset obj's underlying member method code with example usage: obj.__len__() and returns: self