code: def __len__(self):
      return self.n_samples
  
imports: from tempfile import NamedTemporaryFile
  import torch
  from tqdm import tqdm
  import time
  from multiprocessing import cpu_count
  from assertpy import assert_that
  import numpy
  from torch.utils.data import Dataset
  from ffcv import DatasetWriter
  from ffcv.fields import IntField, NDArrayField
  from ffcv import Loader
  from ffcv.fields.basics import IntDecoder
  from ffcv.fields.ndarray import NDArrayDecoder
  from ffcv.loader.loader import OrderOption
  from ffcv.transforms import ToDevice, ToTensor, Squeeze
  import time
label_desc: Use image node_id 2 for calling the DummyArrayDataset obj's underlying member method code with example usage: obj.__len__() and returns: self