code: def set_optimizer(use_multiprecision):
      # init updater on servers
      kv.set_optimizer(
          mx.optimizer.create(
              "test",
              rescale_grad=rate,
              multi_precision=use_multiprecision,
          )
      )
      return kv
  
file_path: mxnet/tests/nightly/dist_sync_kvstore.py
imports: import sys
  import argparse
  import mxnet
  import numpy
  import numpy.random
  from mxnet.test_utils import assert_almost_equal, assert_exception
  from test_kvstore import compute_expected_quantization, compute_1bit, compute_2bit
label_desc: Use image node_id 3 for calling a global function with example usage: set_optimizer(use_multiprecision) and returns: kv