code: def start_processes(
      fn,
      args=(),
      nprocs=1,
      join=True,
      daemon=False,
      start_method="spawn",
  ):
      mp = multiprocessing.get_context(start_method)
      error_files = []
      processes = []
      for i in range(nprocs):
          # Each process is assigned a file to write tracebacks to.  We
          # use the file being non-empty to indicate an exception
          # occurred (vs an expected shutdown).  Note: this previously
          # used a multiprocessing.Queue but that can be prone to
          # deadlocks, so we went with a simpler solution for a one-shot
          # message between processes.
          tf = tempfile.NamedTemporaryFile(
              prefix="pytorch-errorfile-",
              suffix=".pickle",
              delete=False,
          )
          tf.close()
          os.unlink(tf.name)
          process = mp.Process(
              target=_wrap,
              args=(fn, i, args, tf.name),
              daemon=daemon,
          )
          process.start()
          error_files.append(tf.name)
          processes.append(process)
  
      context = ProcessContext(processes, error_files)
      if not join:
          return context
  
      # Loop on join until it returns True or raises an exception.
      while not context.join():
          pass
  
imports: import logging
  import multiprocessing
  import multiprocessing.connection
  import os
  import pickle
  import signal
  import sys
  import tempfile
  import time
  import warnings
  from typing import Optional
  from .None import _prctl_pr_set_pdeathsig
label_desc: Use image node_id 2 for calling a global function with example usage: start_processes(fn, args, nprocs, join, daemon, start_method) and returns: context