python 发送带附件邮件

import smtplib
from email.mime.text import MIMEText
from email.mime.application import MIMEApplication
from email.header import Header

def send_email(filename, message_type='html'):
    # 第三方 SMTP 服务
    mail_host = "smtp.xxx.xxx.xxx"  # 设置服务器
    mail_user = "name@xxx.xxx.xxx"  # 发件邮箱
    mail_pass = "xxxxxx"  # 密码
    receivers = ['name@xxx.xxx.xxx',] # 收件邮箱

    sender = 'name@xxx.xxx.xxx' # 发件邮箱

    message=filename # 邮件内容
    header=filename # 发件人title
    subject=filename # 邮件标题
    
    part = MIMEText(message, message_type, 'utf-8')
    message = MIMEMultipart()

    message['From'] = Header(header, 'utf-8')
    message['Subject'] = Header(subject, 'utf-8')
    message.attach(part)

    attachment=MIMEApplication(open(filename, 'rb').read())
    attachment.add_header('Content-Disposition', 'attachment', filename=filename)
    message.attach(attachment)

    try:
        smtpObj = smtplib.SMTP()
        smtpObj.connect(mail_host, 25)  # 25 为 SMTP 端口号
        smtpObj.login(mail_user, mail_pass)
        smtpObj.sendmail(sender, receivers, message.as_string())
        print("邮件发送成功")
        return True
    except smtplib.SMTPException:
        print("Error: 无法发送邮件")
        return False

if __name__ == '__main__':
    send_email('test.txt')