message: update dataset_ops.py
  Code consistency
diff: @@ -1656,7 +1656,7 @@ name=None))
  stays the same. For example, to flatten a dataset of batches into a
  dataset of their elements:
  - >>> dataset = Dataset.from_tensor_slices([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
  + >>> dataset = tf.data.Dataset.from_tensor_slices([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
  >>> dataset = dataset.flat_map(lambda x: Dataset.from_tensor_slices(x))
  >>> list(dataset.as_numpy_iterator())
  [1, 2, 3, 4, 5, 6, 7, 8, 9]
  