code: def read_cache(self, file_name, variables):
      retry = 1
      while True:
          if retry > 10:
              logger.log(99, "read_cache() retry count over give up.")
              logger.log(
                  99,
                  "Cache file {} not found. pid={}".format(
                      file_name, os.getpid()
                  ),
              )
              logger.log(99, "Fatal Error! send SIGKILL to myself.")
              os.kill(os.getpid(), 9)
  
          result = {}
          try:
              with FileReader(file_name).open(textmode=False) as f:
                  for v in variables:
                      result[v] = numpy.load(f, allow_pickle=True)
              if set(result.keys()) == set(variables):
                  break
              else:
                  logger.log(
                      99,
                      "read_cache() fails retrying count {}/10.".format(
                          retry
                      ),
                  )
                  retry += 1
                  sleep(0.5)
          except:
              logger.log(
                  99,
                  "Cache file {} not found, retry count {}.".format(
                      file_name, retry
                  ),
              )
              retry += 1
              sleep(0.5)
  
      return result
  
imports: import atexit
  import csv
  import os
  import threading
  from collections import OrderedDict, deque
  from time import sleep
  import numpy
  from nnabla.config import nnabla_config
  from nnabla.logger import logger
  from nnabla.utils.communicator_util import current_communicator
  from six.moves import queue
  from .data_source import DataSource
  from .data_source_loader import FileReader, load
label_desc: Use image node_id 2 for calling the CachePrefetcher obj's underlying member method code with example usage: obj.read_cache(file_name, variables) and returns: result