pythonデバッグpythonメールにsmtplibが表示されます.SMTPServer Disconnected:Connection unexpectedly closed問題の解決方法

#coding: utf-8
import smtplib
from email.mime.text import MIMEText
from email.header import Header

#       
receiver = '[email protected]'
sender = '[email protected]'

#      SMTP   （ sender SMTP   ）
smtpserver = 'smtp.qq.com'

#             （         ）
username = '[email protected]'
password = 'moxxxxxxxxxxxfcd'       #（[email protected]      ）

mail_title = '      ！'
mail_body = '       '

#      
message = MIMEText( mail_body, 'plain', 'utf-8' )   #    
# (plain  mail_body       ，    text， mail_body               ，    ）
message ['From'] = sender                                               #         
message['To'] = receiver                                                   #         
message['Subject'] = Header( mail_title, 'utf-8' )   #    

smtp = smtplib.SMTP()                                                     #      
smtp.connect( smtpserver )                                            #          
smtp.login( username, password )                                #     
smtp.sendmail( sender, receiver, message.as_string() )      #            
smtp.quit()

実行結果:
D:\Python\python3.exe "D:/PyCharm files/face/raspberry/smtp.py"Traceback (most recent call last):   File "D:/PyCharm files/face/raspberry/smtp.py", line 43, in     smtp.login(username,password)#ログインサーバFile"D:Pythonlibsmtplib.py",line 721,in login initial_response_ok=initial_response_ok)   File "D:\Python\lib\smtplib.py", line 631, in auth     (code, resp) = self.docmd("AUTH", mechanism + ""+ response)   File "D:\Python\lib\smtplib.py", line 421, in docmd     return self.getreply()   File "D:\Python\lib\smtplib.py", line 394, in getreply     raise SMTPServerDisconnected("Connection unexpectedly closed")
smtplib.SMTPServerDisconnected: Connection unexpectedly closed
ソリューション:
smtp.login(username,password)の前に2行のコードを追加すると、メールの正常な送信が実現します.追加されたコードは次のとおりです.

smtp.ehlo()
smtp.starttls()