class_docstr: Base class of snapshot writers which use thread or process.
  
  This class creates a new thread or a process every time when ``__call__``
  is invoked.
  
  Args:
      savefun: Callable object. It takes three arguments: the output file
          path, the serialized dictionary object, and the optional keyword
          arguments.
      kwds: Keyword arguments for the ``savefun``.
  
  .. seealso::
  
      - :meth:`chainer.training.extensions.snapshot`
docstr: Creates a worker for the snapshot.
  
  This method creates a thread or a process to take a snapshot. The
  created worker must have :meth:`start` and :meth:`join` methods.
  
  Args:
      filename (str): Name of the file into which the serialized target
          is saved. It is already formated string.
      outdir (str): Output directory. Passed by `trainer.out`.
      target (dict): Serialized object which will be saved.
      kwds: Keyword arguments for the ``savefun``.
docstr_tok: ["Creates","a","worker","for","the","snapshot",".","This","method","creates","a","thread","or","a","process","to","take","a","snapshot",".","The","created","worker","must","have",":","meth",":","`","start","`","and",":","meth",":","`","join","`","methods",".","Args",":","filename","(","str",")",":","Name","of","the","file","into","which","the","serialized","target","is","saved",".","It","is","already","formated","string",".","outdir","(","str",")",":","Output","directory",".","Passed","by","`","trainer.out","`",".","target","(","dict",")",":","Serialized","object","which","will","be","saved",".","kwds",":","Keyword","arguments","for","the","``","savefun","``","."]
code: def create_worker(self, filename, outdir, target, **kwds):
      """Creates a worker for the snapshot.
  
      This method creates a thread or a process to take a snapshot. The
      created worker must have :meth:`start` and :meth:`join` methods.
  
      Args:
          filename (str): Name of the file into which the serialized target
              is saved. It is already formated string.
          outdir (str): Output directory. Passed by `trainer.out`.
          target (dict): Serialized object which will be saved.
          kwds: Keyword arguments for the ``savefun``.
  
      """
      raise NotImplementedError
  
imports: import multiprocessing
  import os
  import shutil
  import threading
  from six.moves import queue
  from chainer.serializers import npz
  from chainer import utils
label_desc: Use image node_id 3 for calling the StandardWriter obj's underlying member method code with example usage: obj.create_worker(filename, outdir, target) without return types