code: def test_sequential(self):
      i_iter, s_iter = unzip(self.iterable)
  
      ints = list(i_iter)
      self.assertEqual(ints, self.ints)
  
      strs = list(s_iter)
      self.assertEqual(strs, self.strs)
  
imports: import random
  import unittest
  from chainer import testing
  from chainercv.utils import unzip
label_desc: Use image node_id 2 for calling the TestUnzip obj's underlying member method code with example usage: obj.test_sequential() without return types