code: def previous_epoch_detail(self):
      if self._previous_epoch_detail < 0:
          return None
      return self._previous_epoch_detail
  
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 5 for calling the ParallelSequentialIterator obj's underlying member method code with example usage: obj.previous_epoch_detail() and returns: self, None