class_docstr: The DSprites dataset, mapping images to the latent vector used to generate the image
code: def __len__(self):
      return self.images.shape[0]
  
imports: import argparse
  import os
  from typing import Set
  import numpy
  from PIL import Image
  from torch.utils.data import DataLoader, Dataset
  from tqdm import tqdm
  from vissl.utils.download import download_and_extract_archive
label_desc: Use image node_id 2 for calling the DSprites obj's underlying member method code with example usage: obj.__len__() and returns: self