code: def resolve_master(master, tpu_name, tpu_zone, gcp_project):
      """Resolve the master's URL given standard flags."""
      if master is not None:
          return master
      elif tpu_name is not None:
          return tf.distribute.cluster_resolver.TPUClusterResolver(
              tpu=[tpu_name], zone=tpu_zone, project=gcp_project
          ).get_master()
      else:
          # For k8s TPU we do not have/need tpu_name. See
          # https://cloud.google.com/tpu/docs/kubernetes-engine-setup#tensorflow-code
          return (
              tf.distribute.cluster_resolver.TPUClusterResolver().get_master()
          )
  
imports: import json
  from typing import Optional
  from absl import logging
  import numpy
  import tensorflow
  from deepvariant.protos import deepvariant_pb2
  from third_party.nucleus.io import sharded_file_utils
  from third_party.nucleus.io import tfrecord
  from third_party.nucleus.protos import variants_pb2
  from tensorflow.core.example import example_pb2
label_desc: Use image node_id 24 for calling a global function with example usage: resolve_master(master, tpu_name, tpu_zone, gcp_project) and returns: master, tf, tf