code: def __len__(self) -> int:
      return len(self.file_paths)
  
imports: from typing import Callable, Dict
  import torch
  from torch.utils.data import Dataset
  import torchvision.transforms.functional
  from torchvision import transforms
  import pytorch_lightning
  from collections.abc import Iterable
  from pathlib import Path
  from PIL import Image
  from typing import Tuple
label_desc: Use image node_id 3 for calling the ImageDataset obj's underlying member method code with example usage: obj.__len__() and returns: len