制作数据集时报错AttributeError: 'str' object has no attribute 'write'

代码如下
import os
import tensorflow as tf
from PIL import Image
import matplotlib.pyplot as plt
import numpy as np

#cwd='./data/train/'
cwd='./data/test/'
classes={'mask','nomask'} #人为设定2类
#writer= tf.python_io.TFRecordWriter("mask_and_nomask_test.tfrecords") #要生成的文件
writer= tf.compat.v1.python_io.TFRecordWriter=("mask_and_nomask_test.tfrecords") #要生成的文件

for index,name in enumerate(classes):
class_path=cwd+name+'/'
for img_name in os.listdir(class_path):
img_path=class_path+img_name #每一个图片的地址

img=Image.open(img_path)
img= img.resize((128,128))
print(np.shape(img))
img_raw=img.tobytes()
example = tf.train.Example(features=tf.train.Features(feature={
"label": tf.train.Feature(int64_list=tf.train.Int64List(value=[index])),
'img_raw': tf.train.Feature(bytes_list=tf.train.BytesList(value=[img_raw]))
}))
writer.write(example.SerializeToString())

writer.close()


报错如下
writer.write(example.SerializeToString()) #序列化为字符串

AttributeError: 'str' object has no attribute 'write'


谢谢各位大佬