old_contents: from django.db import models
  
  # Create your models here.
  
  class Contact(models.Model):
  
      name = models.CharField(max_length=512)
      is_organization = models.BooleanField(default=True)
  
      def __unicode__(self):
          return unicode(self.name)
  
new_contents: from django.db import models
  from bitemporal.models import BitemporalModelBase
  
  # Create your models here.
  
  class Contact(BitemporalModelBase):
  
      name = models.CharField(max_length=512)
      is_organization = models.BooleanField(default=True)
  
      def __unicode__(self):
          return unicode(self.name)
  
subject: test of contact model