code: def __len__(self):
      return len(self.video_instances)
  
imports: import os
  import threading
  import warnings
  import weakref
  from fractions import Fraction
  from typing import Any, Dict, List, Tuple
  import numpy
  import torch
  import torchvision
  from PIL import Image
  from torch.utils.data import DataLoader, Dataset
  from torchvision import datasets, io
  from tqdm import tqdm
label_desc: Use image node_id 2 for calling the _TimestampFpsFromVideosDataset obj's underlying member method code with example usage: obj.__len__() and returns: len