是否可以在没有SMTP设置的情况下发送邮件？

import os
from sendgrid import SendGridAPIClient
from sendgrid.helpers.mail import Mail

def send_email(to_email, subject, content):
    message = Mail(
        from_email='your_email@example.com',
        to_emails=to_email,
        subject=subject,
        html_content=content)

    try:
        sg = SendGridAPIClient(os.environ.get('SENDGRID_API_KEY'))
        response = sg.send(message)
        print(response.status_code)
        print(response.body)
        print(response.headers)
    except Exception as e:
        print(e.message)

# 示例调用
send_email('recipient@example.com', 'Hello World', '<strong>This is a test email</strong>')