Django '；CustomEmailBackend'；对象没有属性'；请求'；

我正在尝试将smtp后端子类化为django，并且我希望能够访问self.request或request，我遇到以下错误：

'CustomEmailBackend' object has no attribute 'request'

这是我的EmailBackend的子类

    from django.core.mail.backends.smtp import EmailBackend

    class CustomEmailBackend(EmailBackend):
    
        def send_messages(self, email_messages):
            if not email_messages:
                return 0
            with self._lock:
                new_conn_created = self.open()
                if not self.connection or new_conn_created is None:
                    return 0
                num_sent = 0
                for message in email_messages:
    
                    #set default for this message
                    deliverable = True
    
                    #get list of recipients on message                
                    recipients = message.recipients()
    
                    for recipient in recipients:
                        emailvalidation = email_validation(recipient)
    
                        if emailvalidation.result == "Safe to Send":
                            pass
                          
                        else:
                            deliverable = False
                            
                        if deliverable == True:
                            sent = self._send(message)
                            if sent:
                                num_sent += 1
    
                        else:                                
                            messages.error(self.request, 'Email address invalid. Email was not sent.')
    
                if new_conn_created:
                    self.close()
            return num_sent