code: def serialize(self, serializer):
      # It is important to serialize the state to be recovered on resume.
      self.iteration = serializer("iteration", self.iteration)
      self.epoch = serializer("epoch", self.epoch)
      try:
          self._previous_epoch_detail = serializer(
              "previous_epoch_detail", self._previous_epoch_detail
          )
      except KeyError:
          # guess previous_epoch_detail for older version
          self._previous_epoch_detail = self.epoch + (
              self.current_position - self.batch_size
          ) / len(self.dataset)
          if self.epoch_detail > 0:
              self._previous_epoch_detail = max(
                  self._previous_epoch_detail, 0.0
              )
          else:
              self._previous_epoch_detail = -1.0
  
imports: from __future__ import division
  import argparse
  import sys
  import numpy
  import chainer
  import chainer.functions
  import chainer.links
  from chainer import training
  from chainer.training import extensions
  import chainerx
label_desc: Use image node_id 7 for calling the ParallelSequentialIterator obj's underlying member method code with example usage: obj.serialize(serializer) without return types