code: def get_mnist_iterator():
      train_set = MNIST(train=True, transform=dummy_transform)
      train_iter = gluon.data.DataLoader(
          train_set,
          args.batch_size,
          True,
          num_workers=args.j,
          last_batch="discard",
      )
      val_set = MNIST(train=False, transform=dummy_transform)
      val_iter = gluon.data.DataLoader(
          val_set, args.batch_size, False, num_workers=args.j
      )
  
      return train_iter, val_iter, len(train_set)
  
file_path: byteps/example/mxnet/train_gluon_mnist_byteps_gc.py
imports: import argparse
  import logging
  import subprocess
  import time
  import mxnet
  from mxnet import autograd, gluon, nd
  from mxnet.gluon.data.vision import MNIST
  import byteps.mxnet
label_desc: Use image node_id 2 for calling a global function with example usage: get_mnist_iterator() and returns: train_iter,  val_iter,  len