我通过 python 程序发送一个名为test.txt附件的文件。它成功发送，但当我在 Gmail 收件箱中收到它时，附件显示Untitled的是text.txt. 我的电子邮件代码块如下，看起来是正确的。有什么建议么？
# Setup the email
mail_content = '''Hello,
The attached document contains the results of the file scan.
Please contact the IT Help Desk if you have any questions.
Thank You!!!
'''
message = MIMEMultipart()
message['From'] = sender_address
message['To'] = receiver_address
message['Subject'] = 'A test mail sent by Python. It has an attachment.'
message.attach(MIMEText(mail_content, 'plain'))
attach_file_name = 'david.txt'
# attach_file_name = file_name
attach_file = open(attach_file_name, 'rb') # Open the …