code: def send_email(self, to, subject, content, files=None):
          
          msg = EmailSender._construct_msg(self, to, subject, content, files=files)
          try:
              self.smtp.sendmail(self.from_, to, str(msg))
          except:
              self.login()
              self.smtp.sendmail(self.from_, to, str(msg))
docs: 登录邮箱，发送msg到指定联系人
  
          :param to: str: 收件人邮箱
          :param subject: str: 主题
          :param content: str: 内容
          :param files:  list: 附件列表
          :return: None