code: def testValidDataFormatChannelsLast(self, data_format):
      test = batch_norm.BaseBatchNorm(
          moving_mean=TestMetric(),
          moving_variance=TestMetric(),
          create_scale=False,
          create_offset=False,
          data_format=data_format,
      )
  
      self.assertEqual(test._channel_index, -1)
  
imports: import itertools
  from absl.testing import parameterized
  import numpy
  from sonnet.src import batch_norm
  from sonnet.src import initializers
  from sonnet.src import test_utils
  import tensorflow
label_desc: Use image node_id 13 for calling the BaseBatchNormTest obj's underlying member method code with example usage: obj.testValidDataFormatChannelsLast(data_format) without return types