code: def testNormalizeDataFormat(self):
      self.assertEqual(
          "channels_last", utils.normalize_data_format("Channels_Last")
      )
      self.assertEqual(
          "channels_first",
          utils.normalize_data_format("CHANNELS_FIRST"),
      )
  
      with self.assertRaises(ValueError):
          utils.normalize_data_format("invalid")
  
file_path: tensorflow/tensorflow/python/layers/utils_test.py
imports: from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import test_util
  from tensorflow.python.layers import utils
  from tensorflow.python.ops import array_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 3 for calling the ConvUtilsTest obj's underlying member method code with example usage: obj.testNormalizeDataFormat() without return types