def send_mail(self, subject, content, mail_address):
     if not self.use_email:
         return
     if self.debug:
         mail_address = '*****@*****.**'
     print('email AI: sending email to {}...'\
           .format(mail_address))
     emailAI = Email(receiver=mail_address,
                     sender='*****@*****.**',
                     subject=subject,
                     content=content)
     emailAI.conn_server(host='smtp.qq.com', port=587)
     emailAI.login(username='******',
                   password='******')
     emailAI.send()
     emailAI.close()