如何在python 3.6.2中添加更改内容到自动邮件(smtplib)？

import smtplib
from email.mime.text import MIMEText

def send_email(sender_email, sender_password, receiver_email, subject, content):
    # 创建邮件内容
    message = MIMEText(content, 'plain')
    message['Subject'] = subject
    message['From'] = sender_email
    message['To'] = receiver_email

    # 连接SMTP服务器并发送邮件
    with smtplib.SMTP('smtp.example.com', 587) as server:
        server.starttls()
        server.login(sender_email, sender_password)
        server.sendmail(sender_email, receiver_email, message.as_string())

# 设置发件人和收件人信息
sender_email = 'your_email@example.com'
sender_password = 'your_email_password'
receiver_email = 'recipient_email@example.com'

# 设置邮件主题和内容
subject = '自动邮件测试'
content = '这是一封通过Python自动发送的邮件。'

# 发送邮件
send_email(sender_email, sender_password, receiver_email, subject, content)