code: def timeout_if_down(self, node):
      if node.id in self.nodes_timeout:
          raise exceptions.TimeoutError
  
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 3 for calling the SentinelTestCluster obj's underlying member method code with example usage: obj.timeout_if_down(node) without return types