def serving_input_receiver_fn():
    image_bytes_list = tf.placeholder(shape=[None], dtype=tf.string)
    images = tf.map_fn(_preprocess_image, image_bytes_list, back_prop=False, dtype=dtype)
    return tf.estimator.export.TensorServingInputReceiver(features=images, receiver_tensors=image_bytes_list)
def serving_input_receiver_fn():
    image_bytes_list = tf.placeholder(shape=[None], dtype=tf.string)
    images = tf.map_fn(_preprocess_image, image_bytes_list, back_prop=False, dtype=dtype)
    return tf.estimator.export.TensorServingInputReceiver(features=images, receiver_tensors=image_bytes_list)