code: def testTaskTypeCastToString(self):
      os.environ[
          "TF_CONFIG"
      ] = """
      {
        "cluster": {
          "123456": ["ps0:2222", "ps1:2222"],
          "worker": ["worker0:2222", "worker1:2222", "worker2:2222"]
        },
        "rpc_layer": "grpc",
        "task": {
          "type": 123456,
          "index": 0
        }
      }
      """
      cluster_resolver = (
          tfconfig_cluster_resolver.TFConfigClusterResolver()
      )
      self.assertEqual("123456", cluster_resolver.task_type)
  
imports: import os
  from tensorflow.python.client import session
  from tensorflow.python.distribute.cluster_resolver import tfconfig_cluster_resolver
  from tensorflow.python.eager import context
  from tensorflow.python.framework import config
  from tensorflow.python.framework import test_util
  from tensorflow.python.platform import test
  from tensorflow.python.training import server_lib
label_desc: Use image node_id 10 for calling the TFConfigClusterResolverTest obj's underlying member method code with example usage: obj.testTaskTypeCastToString() without return types