code: def test_old_unpickle(self):
      embed = links.EmbedID(3, 4)
      # To emulate an old pickled file
      delattr(embed, "ignore_label")
      x = chainer.Variable(numpy.arange(2, dtype=numpy.int32))
      y = embed(x)
      self.assertEqual(y.data.shape, (2, 4))
  
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import gradient_check
  from chainer import links
  from chainer import testing
  from chainer.testing import attr
  from chainer.testing import condition
label_desc: Use image node_id 1 for calling the TestEmbedIDUnpickleOldFile obj's underlying member method code with example usage: obj.test_old_unpickle() without return types