code: def _set_state(
      self, state: bytes, token: Optional[Any] = None
  ) -> Tuple[bytes, Token, bool]:
      result = self._backend.set_state(state, token)
  
      self.assertIsNotNone(result)
  
      return cast(Tuple[bytes, Token, bool], result)
  
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 2 for calling the RendezvousBackendTestMixin obj's underlying member method code with example usage: obj._set_state(state, token) and returns: cast