class_docstr: Joinable train loop.
class_docstr_tok: ["Joinable","train","loop","."]
code: def join_device(self) -> torch.device:
      return self.__device
  
imports: import contextlib
  import functools
  import torch
  import torch.distributed
  from torch.distributed.algorithms.join import Join, Joinable, JoinHook
  import torch.nn
  from parlai.scripts.eval_model import Evaluator
  from parlai.scripts.train_model import TrainLoop
  from parlai.utils.distributed import is_distributed, get_dist_group
label_desc: Use image node_id 4 for calling the JoinableTrainLoop obj's underlying member method code with example usage: obj.join_device() and returns: self