使用smtp python发送电子邮件，def块有问题

import smtplib
from email.mime.text import MIMEText

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

    try:
        # 连接SMTP服务器
        server = smtplib.SMTP('smtp.example.com', 587)  # 替换为实际的SMTP服务器地址和端口
        server.starttls()
        # 登录SMTP服务器
        server.login(sender_email, sender_password)
        # 发送邮件
        server.sendmail(sender_email, receiver_email, msg.as_string())
        # 关闭连接
        server.quit()
        print("邮件发送成功！")
    except Exception as e:
        print("邮件发送失败：", str(e))

# 调用发送邮件函数
send_email("sender@example.com", "password", "receiver@example.com", "测试邮件", "这是一封测试邮件。")