code: def __len__(self):
      return self.length
  
imports: from ffcv.transforms.ops import ToTensor
  from ffcv.fields.rgb_image import RandomResizedCropRGBImageDecoder, SimpleRGBImageDecoder, CenterCropRGBImageDecoder
  import numpy
  import torch
  from torch.utils.data import Dataset
  from assertpy import assert_that
  from tempfile import NamedTemporaryFile
  from torchvision.datasets import CIFAR10
  from torch.utils.data import Subset
  from ffcv.writer import DatasetWriter
  from ffcv.fields import IntField, RGBImageField
  from ffcv.loader import Loader
  from ffcv.pipeline.compiler import Compiler
label_desc: Use image node_id 2 for calling the DummyDataset obj's underlying member method code with example usage: obj.__len__() and returns: self