old_contents: from django.db import models
  from django.utils.translation import ugettext_lazy as _
  
  
  class Subscription(models.Model):
      email = models.EmailField(_("email address"), unique=True)
      date_subscribed = models.DateTimeField(_("date subscribed"), auto_now_add=True)
  
new_contents: from django.db import models
  from django.utils.translation import ugettext_lazy as _
  
  
  class Subscription(models.Model):
      email = models.EmailField(_("email address"), unique=True)
      date_subscribed = models.DateTimeField(_("date subscribed"), auto_now_add=True)
  
      def __str__(self):
          return f"{self.email} subscribed on {self.date_subscribed}"
  
subject: Fix admin newsletter