Python电子邮件的大小远远大于使用smtplib的zip文件

Question

因此，我有以下使用smtplib发送带有zip附件的电子邮件的代码。但问题是，我得到了一个错误，超过了限制大小，但zip文件只有500KB，但当我打印邮件的总大小在最后，我看到35MB！！。非常感谢在理解这一点上的任何帮助！谢谢

zf = open(newZip+".zip","rb")

msg = MIMEMultipart()
msg['From'] = os.environ['EMAIL_USER']
msg['To'] = email
msg['Date'] = formatdate(localtime = True)
msg['Subject'] = "Results - "+email
msg.attach (MIMEText("textMessage"))

part = MIMEBase('application', "octet-stream")
part.set_payload(zf.read())
encoders.encode_base64(part)
part.add_header('Content-Disposition', 'attachment; filename='+newZip+".zip")
msg.attach(part)

server = smtplib.SMTP_SSL("smtp.gmail.com", 465)
server.ehlo()
server.login(os.environ['EMAIL_USER'], os.environ['EMAIL_PASSWORD'])
server.sendmail(os.environ['EMAIL_USER'], email, str(msg))

max_limit_in_bytes = int( server.esmtp_features['size'] )
print(max_limit_in_bytes)
print("***********")

server.close()