code: def test_pushpull():
      def check_default_keys(nrepeat=3):
          # init kv dns keys
          kv.broadcast(
              "3",
              mx.nd.ones(shape, ctx=get_current_device(device=True)),
              mx.nd.ones(shape, ctx=get_current_device(device=True)),
          )
          kv.broadcast(
              "99",
              mx.nd.ones(
                  big_shape, ctx=get_current_device(device=True)
              ),
              mx.nd.ones(
                  big_shape, ctx=get_current_device(device=True)
              ),
          )
          for _ in range(nrepeat):
              scale = my_rank + 1
              num = (my_num_workers + 1) * my_num_workers / 2
  
              arr = (
                  mx.nd.ones(shape, ctx=get_current_device(device=True))
                  * scale
              )
              # inplace
              kv.pushpull("3", arr)
              check_diff_to_scalar(arr, num)
  
              big_arr = (
                  mx.nd.ones(
                      big_shape, ctx=get_current_device(device=True)
                  )
                  * scale
              )
              # inplace
              kv.pushpull("99", big_arr)
              check_diff_to_scalar(big_arr, num)
  
      check_default_keys(nrepeat=3)
      print("worker " + str(my_rank) + " is done")
  
file_path: mxnet/tests/nightly/dist_device_sync_kvstore_byteps.py
imports: import sys
  import mxnet
  import numpy
  import numpy.random
  import time
  import argparse
  from mxnet.log import get_logger
  import logging
  from mxnet.kvstore import BytePS
label_desc: Use image node_id 3 for calling a global function with example usage: test_pushpull() without return types