code: def test_unreleased(self):
      iter_0, iter_1 = unzip(self.iterable)
  
      for i in range(20):
          next(iter_0)
  
      self.assertEqual(self.released, set())
  
imports: import random
  import unittest
  from chainer import testing
  from chainercv.utils import unzip
label_desc: Use image node_id 3 for calling the TestUnzipRelease obj's underlying member method code with example usage: obj.test_unreleased() without return types