class_docstr: Cluster Resolver for Google Cloud TPUs.
  
  This is an implementation of cluster resolvers for the Google Cloud TPU
  service.
  
  TPUClusterResolver supports the following distinct environments:
  Google Compute Engine
  Google Kubernetes Engine
  Google internal
  
  It can be passed into `tf.distribute.TPUStrategy` to support TF2 training on
  Cloud TPUs.
code: def __deepcopy__(self, memo):
      # TODO(b/73668574): Remove this once RunConfig avoids performing deepcopy.
      return self
  
imports: import collections
  import re
  from tensorflow.core.protobuf.tpu import topology_pb2
  from tensorflow.python.distribute.cluster_resolver import cluster_resolver
  from tensorflow.python.eager import remote
  from tensorflow.python.framework import config
  from tensorflow.python.framework import errors
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.tpu import tpu_strategy_util
  from tensorflow.python.tpu import tpu_system_metadata
  from tensorflow.python.training import server_lib
  from tensorflow.python.util import compat
label_desc: Use image node_id 18 for calling the TPUClusterResolver obj's underlying member method code with example usage: obj.__deepcopy__(memo) and returns: self