如何从outlook - pywin32中将xls附件另存为xlsx

import win32com.client
import os

outlook = win32com.client.Dispatch("Outlook.Application").GetNamespace("MAPI")
outlook.Logon()

inbox = outlook.GetDefaultFolder(6)  # 6表示收件箱
messages = inbox.Items

for message in messages:
    attachments = message.Attachments
    for attachment in attachments:
        if attachment.FileName.endswith('.xls'):
            # 将xls附件另存为xlsx
            new_filename = os.path.splitext(attachment.FileName)[0] + '.xlsx'
            attachment.SaveAsFile(os.path.join('保存路径', new_filename))