code: def size(self, index):
      return 1
  
imports: from functools import partial
  import logging
  import math
  import random
  import time
  import numpy
  import os
  import torch
  from torchvision import datasets, transforms
  from .path_dataset import PathDataset
  from fairseq.data import FairseqDataset
  from fairseq.data.data_utils import compute_block_mask_1d, compute_block_mask_2d
  from shutil import copyfile
label_desc: Use image node_id 6 for calling the MaeImageDataset obj's underlying member method code with example usage: obj.size(index) and returns: int