class_docstr: A class that listens for exceptions in children processes and propagates
  the tracebacks to the parent process.
docstr: init error handler
docstr_tok: ["init","error","handler"]
code: def __init__(self, error_queue):
      """init error handler"""
      import signal
      import threading
  
      self.error_queue = error_queue
      self.children_pids = []
      self.error_thread = threading.Thread(
          target=self.error_listener, daemon=True
      )
      self.error_thread.start()
      signal.signal(signal.SIGUSR1, self.signal_handler)
  
imports: import os
  import signal
  import math
  import pickle
  import torch.distributed
  from datetime import timedelta
  from onmt.translate.translator import build_translator
  from onmt.transforms import get_transforms_cls
  from onmt.constants import CorpusTask
  from onmt.utils.logging import init_logger, logger
  from onmt.inputters.dynamic_iterator import build_dynamic_dataset_iter
label_desc: Use image node_id 1 to create a new ErrorHandler object from inherited base classes: object with example: obj = ErrorHandler(error_queue)