code: def set_epoch(self, epoch):
      self.epoch = epoch
  
imports: import contextlib
  import logging
  import queue
  from typing import Dict, List
  import numpy
  import torch
  from PIL import Image
  from torch.utils.data import Dataset
  from torch.utils.data.distributed import DistributedSampler
label_desc: Use image node_id 3 for calling the StratifiedClassSampler obj's underlying member method code with example usage: obj.set_epoch(epoch) without return types