code: def multiprocess_eval(
      rank,
      opt,
      port=61337,
      rank_offset=0,
      gpu=None,
      hostname="localhost",
  ):
      """
      Run a multiprocessing evaluation.
  
      Invoked by launch_and_eval, not instantiated directly.
      """
      init_method = f"tcp://{hostname}:{port}"
      with distributed_utils.distributed_context(
          rank, opt, rank_offset, gpu, init_method=init_method
      ) as opt:
          opt["multiprocessing"] = True
          evaluator = fsdp_utils.JoinableEvaluator(opt)
          with fsdp_utils.fsdp_join(evaluator):
              return evaluator.eval_model()
  
file_path: ParlAI/parlai/scripts/multiprocessing_eval.py
imports: import torch
  import os
  import signal
  import parlai.scripts.eval_model
  import parlai.utils.distributed
  import parlai.utils.fsdp
  from parlai.core.script import ParlaiScript, register_script
label_desc: Use image node_id 1 for calling a global function with example usage: multiprocess_eval(rank, opt, port, rank_offset, gpu, hostname) and returns: evaluator