//  [python]
def main(_):
  if len(sys.argv) < 2 or sys.argv[-1].startswith('-'):
    print('Usage: mnist_saved_model.py [--training_iteration=x] '
          '[--model_version=y] export_dir')
    sys.exit(-1)
  if FLAGS.training_iteration <= 0:
    print('Please specify a positive value for training iteration.')
    sys.exit(-1)
  if FLAGS.model_version <= 0:
    print('Please specify a positive value for version number.')
    sys.exit(-1)

  # Train model
  print('Training model...')
  mnist = mnist_input_data.read_data_sets(FLAGS.work_dir, one_hot=True)
  sess = tf.InteractiveSession()
  serialized_tf_example = tf.placeholder(tf.string, name='tf_example')
  feature_configs = {'x': tf.FixedLenFeature(shape=[784], dtype=tf.float32),}
  tf_example = tf.parse_example(serialized_tf_example, feature_configs)
  x = tf.identity(tf_example['x'], name='x')  # use tf.identity() to assign name
  y_ = tf.placeholder('float', shape=[None, 10])
  w = tf.Variable(tf.zeros([784, 10]))
  b = tf.Variable(tf.zeros([10]))
  sess.run(tf.global_variables_initializer())
  y = tf.nn.softmax(tf.matmul(x, w) + b, name='y')
  cross_entropy = -tf.reduce_sum(y_ * tf.log(y))
  train_step = tf.train.GradientDescentOptimizer(0.01).minimize(cross_entropy)
  values, indices = tf.nn.top_k(y, 10)
  table = tf.contrib.lookup.index_to_string_table_from_tensor(
      tf.constant([str(i) for i in range(10)]))
  prediction_classes = table.lookup(tf.to_int64(indices))
  for _ in range(FLAGS.training_iteration):
    batch = mnist.train.next_batch(50)
    train_step.run(feed_dict={x: batch[0], y_: batch[1]})
  correct_prediction = tf.equal(tf.argmax(y, 1), tf.argmax(y_, 1))
  accuracy = tf.reduce_mean(tf.cast(correct_prediction, 'float'))
  print('training accuracy %g' % sess.run(
      accuracy, feed_dict={
          x: mnist.test.images,
          y_: mnist.test.labels
      }))
  print('Done training!')

  # Export model
  # WARNING(break-tutorial-inline-code): The following code snippet is
  # in-lined in tutorials, please update tutorial documents accordingly
  # whenever code changes.
  export_path_base = sys.argv[-1]
  export_path = os.path.join(
      tf.compat.as_bytes(export_path_base),
      tf.compat.as_bytes(str(FLAGS.model_version)))
  print('Exporting trained model to', export_path)
  builder = tf.saved_model.builder.SavedModelBuilder(export_path)

  # Build the signature_def_map.
  classification_inputs = tf.saved_model.utils.build_tensor_info(
      serialized_tf_example)
  classification_outputs_classes = tf.saved_model.utils.build_tensor_info(
      prediction_classes)
  classification_outputs_scores = tf.saved_model.utils.build_tensor_info(values)

  classification_signature = (
      tf.saved_model.signature_def_utils.build_signature_def(
          inputs={
              tf.saved_model.signature_constants.CLASSIFY_INPUTS:
                  classification_inputs
          },
          outputs={
              tf.saved_model.signature_constants.CLASSIFY_OUTPUT_CLASSES:
                  classification_outputs_classes,
              tf.saved_model.signature_constants.CLASSIFY_OUTPUT_SCORES:
                  classification_outputs_scores
          },
          method_name=tf.saved_model.signature_constants.CLASSIFY_METHOD_NAME))

  tensor_info_x = tf.saved_model.utils.build_tensor_info(x)
  tensor_info_y = tf.saved_model.utils.build_tensor_info(y)

  prediction_signature = (
      tf.saved_model.signature_def_utils.build_signature_def(
          inputs={'images': tensor_info_x},
          outputs={'scores': tensor_info_y},
          method_name=tf.saved_model.signature_constants.PREDICT_METHOD_NAME))

  builder.add_meta_graph_and_variables(
      sess, [tf.saved_model.tag_constants.SERVING],
      signature_def_map={
          'predict_images':
              prediction_signature,
          tf.saved_model.signature_constants.DEFAULT_SERVING_SIGNATURE_DEF_KEY:
              classification_signature,
      },
      main_op=tf.tables_initializer(),
      strip_default_attrs=True)

  builder.save()

  print('Done exporting!')