message: Update keras to use tf public API.
diff: @@ -60,6 +60,7 @@ from tensorflow.python.keras.utils import losses_utils
  from tensorflow.python.keras.utils import np_utils
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import check_ops
  +from tensorflow.python.ops import io_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import nn
  from tensorflow.python.ops import parsing_ops
  @@ -1607,7 +1608,7 @@ class TestDistributionStrategyWithDatasetsFile(test.TestCase,
  self.input_file_name = os.path.join(self.get_temp_dir(), 'input.tfrecord')
  inputs = np.zeros((20, 3), dtype=np.float32)
  input_dataset = dataset_ops.Dataset.from_tensor_slices(inputs)
  - input_dataset = input_dataset.map(parsing_ops.serialize_tensor)
  + input_dataset = input_dataset.map(io_ops.serialize_tensor)
  writer = writers.TFRecordWriter(self.input_file_name)
  writer.write(input_dataset)
  