code: def test_get_state_returns_backend_state(self) -> None:
      self._backend.set_state(b"x")
  
      result = self._backend.get_state()
  
      self.assertIsNotNone(result)
  
      state, token = cast(Tuple[bytes, Token], result)
  
      self.assertEqual(b"x", state)
      self.assertIsNotNone(token)
  
file_path: pytorch/test/distributed/elastic/rendezvous/rendezvous_backend_test.py
imports: from abc import ABC, abstractmethod
  from typing import Any, Callable, Optional, Tuple, cast
  from torch.distributed.elastic.rendezvous import RendezvousStateError
  from torch.distributed.elastic.rendezvous.dynamic_rendezvous import RendezvousBackend, Token
label_desc: Use image node_id 3 for calling the RendezvousBackendTestMixin obj's underlying member method code with example usage: obj.test_get_state_returns_backend_state() without return types