code: def client(self, host, port, **kwargs):
      return SentinelTestClient(self, (host, port))
  
imports: import socket
  from unittest import mock
  import pytest
  import redis.sentinel
  from redis import exceptions
  from redis.sentinel import MasterNotFoundError, Sentinel, SentinelConnectionPool, SlaveNotFoundError
label_desc: Use image node_id 4 for calling the SentinelTestCluster obj's underlying member method code with example usage: obj.client(host, port) and returns: SentinelTestClient