python 报错：a bytes-like object is required, not 'str'

核心代码：
import csv
import base64

def image_to_base64():
    '''封装把图片转换为base64编码格式'''
    o = open(r'E:Jmeter1.jpg', 'rb')
    base64_data = base64.b64encode(o.read())
    s = base64_data.decode()
    return ("data:image/png;base64,%s"%s)

def base64_write_csv():
    '''把生成的base64写入CSV文件'''
    f = open(r'E:Jmeterimage.csv', 'wb')
    csv_writer = csv.writer(f)
    csv_writer.writerow(['image'])
    csv_writer.writerow([image_to_base64()])
    f.close()

if __name__ == '__main__':
    base64_write_csv()
报错如下：

注意点：
   一定要将str转为bytes
   python36把file方法改为open
   open('xxx.csv', 'wb')将wb改为w就没报错了