message: Update docs for tf.data.experimental.TFRecordWriter
diff: @@ -28,16 +28,25 @@ from tensorflow.python.util.tf_export import tf_export
  @tf_export("data.experimental.TFRecordWriter")
  class TFRecordWriter(object):
  - """Writes data to a TFRecord file.
  + """Writes a dataset to a TFRecord file.
  - To write a `dataset` to a single TFRecord file:
  + The elements of the dataset must be scalar strings. To serialize dataset
  + elements as strings, you can use the `tf.io.serialize_tensor` function.
  ```python
  - dataset = ... # dataset to be written
  - writer = tf.data.experimental.TFRecordWriter(PATH)
  + dataset = tf.data.Dataset.range(3)
  + dataset = dataset.map(tf.io.serialize_tensor)
  + writer = tf.data.experimental.TFRecordWriter("/path/to/file.tfrecord")
  writer.write(dataset)
  ```
  + To read back the elements, use `TFRecordDataset`.
  +
  + ```python
  + dataset = tf.data.TFRecordDataset("/path/to/file.tfrecord")
  + dataset = dataset.map(lambda x: tf.io.parse_tensor(x, tf.int64))
  + ```
  +
  To shard a `dataset` across multiple TFRecord files:
  ```python
  @@ -57,6 +66,14 @@ class TFRecordWriter(object):
  """
  def __init__(self, filename, compression_type=None):
  + """Initializes a `TFRecordWriter`.
  +
  + Args:
  + filename: a string path indicating where to write the TFRecord data.
  + compression_type: (Optional.) a string indicating what type of compression
  + to use when writing the file. See `tf.io.TFRecordCompressionType` for
  + what types of compression are available. Defaults to `None`.
  + """
  self._filename = ops.convert_to_tensor(
  filename, dtypes.string, name="filename")
  self._compression_type = convert.optional_param_to_tensor(
  @@ -66,13 +83,24 @@ class TFRecordWriter(object):
  argument_dtype=dtypes.string)
  def write(self, dataset):
  - """Returns a `tf.Operation` to write a dataset to a file.
  + """Writes a dataset to a TFRecord file.
  +
  + An operation that writes the content of the specified dataset to the file
  + specified in the constructor.
  +
  + If the file exists, it will be overwritten.
  Args:
  dataset: a `tf.data.Dataset` whose elements are to be written to a file
  Returns:
  - A `tf.Operation` that, when run, writes contents of `dataset` to a file.
  + In graph mode, this returns an operation which when executed performs the
  + write. In eager mode, the write is performed by the method itself and
  + there is no return value.
  +
  + Raises
  + TypeError: if `dataset` is not a `tf.data.Dataset`.
  + TypeError: if the elements produced by the dataset are not scalar strings.
  """
  if not isinstance(dataset, dataset_ops.DatasetV2):
  raise TypeError("`dataset` must be a `tf.data.Dataset` object.")
  