code: def test_invalid_batch(self):
      args = self.create_batch((3,), (1, 3))
      with testing.assert_warns(UserWarning):
          functions.batch_normalization(*args)
  
imports: import unittest
  import warnings
  import numpy
  import six
  import chainer
  from chainer.backends import cuda
  from chainer import functions
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
  from chainer.testing import backend
label_desc: Use image node_id 3 for calling the TestBatchNormalizationWarning obj's underlying member method code with example usage: obj.test_invalid_batch() without return types