如何清除MIME Base中的附件

Question

我尝试拨打未接电话服务。从串行端口捕获呼叫者ID并发送电子邮件，然后断开呼叫。它工作正常，但第二封邮件中有第一封邮件的附件，而第三封邮件中有1＆2的附件。我不知道清除的附件数据。

from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
import smtplib
import serial
import time

msg = MIMEMultipart()
msg['from'] = "fromaddr"
msg['to'] = "toaddr"
msg['subject'] = "New Lead"

s = serial.Serial('COM8', baudrate=9600, timeout=1)

def serialEvent():
    data = s.read(20)
    print (data)
    data=""


def send_mail(msgg):
    msgg.attach(MIMEText(inNumber, 'html'))
    server = smtplib.SMTP("host", 587)
    server.starttls()
    server.login(msg['from'],"password")
    server.sendmail(msg['from'], msg['to'], msgg.as_string(), )
    server.quit()
    time.sleep(1)

while True:
    res=""
    res = s.read(150)
    value = (res.decode('utf-8'))
    data = str(value)
    s.flushInput()
    s.flushOutput()
    l=data.find("RING")
    if l>=0:
        inNumber = ""
        inNumber=data[18:31]
        time.sleep(1)
        print (inNumber)
        hang = 'AT+CHUP'+'\r\n'
        s.write(hang.encode())
        send_mail(msg)