code: def __getitem__(self, id_):
      lens = self.lens[id_]
      if self.cached_data is None:
          h5file = load_h5file(self.h5_path)
          features = np.array(h5file[id_])
          h5file.close()
          return features, lens
      return self.cached_data[id_], lens
  
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 2 for calling the BertTextFeatureLoader obj's underlying member method code with example usage: obj.__getitem__(id_) and returns: self,  lens, features,  lens