old_contents: # THIRD PARTY
  from djangae.fields import CharField
  from django.db import models
  
  
  class Secret(models.Model):
      created = models.DateTimeField(auto_now_add=True)
      url_slug = CharField(primary_key=True)
      secret = CharField()
  
      def __unicode__(self):
          return self.url_slug
  
      def clean(self, *args, **kwargs):
          return_value = super(Secret, self).clean(*args, **kwargs)
          if not self.secret.startswith(self.url_slug):
              raise ValidationError("The URL slug and the beginning of the secret should be the same.")
  
new_contents: # THIRD PARTY
  from djangae.fields import CharField
  from django.db import models
  
  
  class Secret(models.Model):
      created = models.DateTimeField(auto_now_add=True)
      url_slug = CharField(primary_key=True)
      secret = CharField()
  
      class Meta(object):
          ordering = ('-created',)
  
      def __unicode__(self):
          return self.url_slug
  
      def clean(self, *args, **kwargs):
          return_value = super(Secret, self).clean(*args, **kwargs)
          if not self.secret.startswith(self.url_slug):
              raise ValidationError("The URL slug and the beginning of the secret should be the same.")
  
subject: Order Secret objects by `created` date.