code: def testInitializeIpAddress(self):
      c = client.Client(tpu="grpc://1.2.3.4:8470")
      self.assertEqual("grpc://1.2.3.4:8470", c._tpu)
      self.assertEqual(False, c._use_api)
      self.assertIsNone(c._service)
      self.assertIsNone(c._credentials)
      self.assertIsNone(c._project)
      self.assertIsNone(c._zone)
      self.assertIsNone(c._discovery_url)
      self.assertEqual(
          [{"ipAddress": "1.2.3.4", "port": "8470"}],
          c.network_endpoints(),
      )
  
imports: import datetime
  import json
  import os
  import time
  import urllib
  from absl import flags
  from tensorflow.python.platform import test
  from tensorflow.python.tpu.client import client
label_desc: Use image node_id 21 for calling the CloudTpuClientTest obj's underlying member method code with example usage: obj.testInitializeIpAddress() without return types