old_contents: from django.db import models
  from django.contrib.auth.models import User
  from django.core.mail import send_mail
  from django.conf import settings
  
  
  class Feedback(models.Model):
      message = models.TextField()
      owner = models.ForeignKey(
          User,
          blank=True,
          null=True,
          on_delete=models.deletion.CASCADE
      )
  
      def __str__(self):
          if self.owner:
              return self.owner.username + ': ' + self.message
          else:
              return 'Anonymous: ' + self.message
  
      def save(self, *args, **kwargs):
          reply_to = ''
          if self.owner:
              from_sender = self.owner.username
              if self.owner.email and self.owner.email:
                  reply_to = ' (' + self.owner.email + ')'
          else:
              from_sender = 'Anonymous'
          send_mail('Feedback from ' + from_sender + reply_to,
                    self.message,
                    settings.DEFAULT_FROM_EMAIL,
                    [settings.CONTACT_EMAIL],
                    fail_silently=True)
          super(Feedback, self).save(*args, **kwargs)
  
new_contents: from django.db import models
  from django.contrib.auth.models import User
  from django.core.mail import send_mail
  from django.conf import settings
  
  
  class Feedback(models.Model):
      message = models.TextField()
      owner = models.ForeignKey(
          User,
          blank=True,
          null=True,
          on_delete=models.deletion.CASCADE
      )
  
      def __str__(self):
          if self.owner:
              return self.owner.username + ': ' + self.message
          else:
              return 'Anonymous: ' + self.message
  
      def save(self, *args, **kwargs):
          reply_to = ''
          if self.owner:
              from_sender = self.owner.username
              if self.owner.email:
                  reply_to = ' (' + self.owner.email + ')'
          else:
              from_sender = 'Anonymous'
          send_mail('Feedback from ' + from_sender + reply_to,
                    self.message,
                    settings.DEFAULT_FROM_EMAIL,
                    [settings.CONTACT_EMAIL],
                    fail_silently=True)
          super(Feedback, self).save(*args, **kwargs)
  
subject: remove double check