old_contents: from django.db import models
  
  
  class Lease(models.Model):
      class Meta:
          db_table = 'autoreg'
  
      mac = models.CharField(max_length=17, db_index=True)
      ip = models.IntegerField(primary_key=True)
      date = models.IntegerField()
  
new_contents: from django.db import models
  from ipaddr import IPv4Address
  
  
  class Lease(models.Model):
      class Meta:
          db_table = 'autoreg'
  
      mac = models.CharField(max_length=17, db_index=True)
      ip = models.IntegerField(primary_key=True)
      date = models.IntegerField()
  
      def __str__(self):
          return unicode(self).encode('ascii', 'replace')
  
      def __unicode__(self):
          return unicode(IPv4Address(self.ip)) + u' = ' + unicode(self.mac)
  
      def __repr__(self):
          return u'<Lease: ' + unicode(self) + u'>'
  
subject: Add __str__, __unicode__, and __repr__