code: def __len__(self):
      return len(self.ids)
  
imports: import json
  from collections import OrderedDict
  from pathlib import Path
  from typing import List
  import re
  import numpy
  import torch
  import torch.utils.data
  from tqdm import tqdm
  from gluoncv.torch.utils import coot_utils
label_desc: Use image node_id 6 for calling the VideoDatasetFeatures obj's underlying member method code with example usage: obj.__len__() and returns: len