code: def _worker(cls, batch_idx, batch):
      process_name = multiprocessing.current_process().name
      # print("[_worker] called %s. images in batch: %d" % (process_name, len(batch.images_unaug),))
      if "-1" in process_name:
          for image in batch.images_unaug:
              image[::4, ::4, :] = [255, 255, 255]
      return multicore.Pool._worker(batch_idx, batch)
  
file_path: imgaug/checks/check_multicore_pool.py
imports: from __future__ import print_function, division
  import time
  import multiprocessing
  import numpy
  from skimage import data
  import imgaug
  import imgaug.multicore
  from imgaug import augmenters
label_desc: Use image node_id 2 for calling the PoolWithMarkedWorker obj's underlying member method code with example usage: obj._worker(cls, batch_idx, batch) and returns: multicore