如何对Python脚本应用筛选器以下载特定电子邮件附件

import imaplib
import email

# 邮件服务器的地址和认证信息
mail_server = 'mail.example.com'
username = 'your_username'
password = 'your_password'

# 连接到邮件服务器
mail = imaplib.IMAP4_SSL(mail_server)
mail.login(username, password)

# 选择邮箱
mail.select('INBOX')

# 使用搜索条件筛选邮件
status, data = mail.search(None, 'SUBJECT "特定邮件主题"')
email_ids = data[0].split()

# 遍历筛选出的邮件列表
for email_id in email_ids:
    # 获取邮件内容
    status, data = mail.fetch(email_id, '(RFC822)')
    raw_email = data[0][1]
    email_message = email.message_from_bytes(raw_email)

    # 判断是否有附件
    if email_message.get_content_maintype() == 'multipart':
        for part in email_message.walk():
            if part.get_content_maintype() == 'multipart' or part.get('Content-Disposition') is None:
                continue
            # 下载附件
            filename = part.get_filename()
            if filename:
                with open(filename, 'wb') as f:
                    f.write(part.get_payload(decode=True))

# 关闭连接
mail.logout()