message: Use new flat structure API
diff: @@ -125,7 +125,8 @@ tf.Dataset.batch, set `drop_remainder=True`.""".format(output_shape))
  with ops.device('/device:CPU:0'):
  self._replication_factor = replication_factor
  self._dataset = dataset
  - self._structure = dataset_ops.get_structure(dataset)
  + self._structure = dataset_ops.get_structure(self._dataset)
  + self._flat_structure = dataset._flat_structure
  # Batch the dataset to take replication into account.
  if self._replication_factor > 1:
  self._dataset = self._dataset.batch(
  @@ -163,7 +164,7 @@ tf.Dataset.batch, set `drop_remainder=True`.""".format(output_shape))
  flat_ret = gen_pop_datastream_ops.pop_datastream_infeed_dequeue(
  feed_id=self._id,
  replication_factor=self._replication_factor,
  - **self._dataset._flat_structure)
  + **self._flat_structure)
  self._dequeued = True
  return structure.from_tensor_list(self._structure, flat_ret)
  