code: def __len__(self):
      return self.len_1 + self.len_2
  
imports: import glob
  import logging
  import os
  import random
  import cv2
  import io
  import numpy
  import hashlib
  import lmdb
  import pickle
  import torch
  import torch.nn.functional
  from torch.utils.data import Dataset, IterableDataset, DataLoader, DistributedSampler, ConcatDataset
  import torchvision.transforms
  from torchvision.transforms import Compose, ToTensor, Normalize, RandomResizedCrop
  from PIL import Image
  from enum import Enum
  import csv
  import pandas
  import json
label_desc: Use image node_id 3 for calling the Text2ImgTrainDataset obj's underlying member method code with example usage: obj.__len__() and returns: unknown