Tensorflow实战(1)-Load NumPy Array In Dataset Parser Function

def parser(image_file, label_file):
    image_data = tf.read_file(image_file)
    image_data = tf.image.decode_jpeg(image_data)
    image_data = tf.image.convert_image_dtype(image_data, tf.float32)
    ...
    label_data = np.load(label_file)
    ...
    return image_data, label_data
 
image_holder = tf.placeholder(tf.string)
label_holder = tf.placeholder(tf.string)
dataset = tf.data.Dataset.from_tensor_slices((image_holder, label_holder))
dataset = dataset.map(parser)

AttributeError: 'Tensor' object has no attribute 'read'

label_data = tf.py_func(np.load, [label_file], [tf.float32])