old_contents: """
  Modoboa API models.
  """
  from django.db import models
  
  from versionfield import VersionField
  
  
  class ModoboaInstance(models.Model):
  
      """
      A model to represent a modoboa instance.
      """
  
      hostname = models.CharField(max_length=255)
      ip_address = models.IPAddressField()
      known_version = VersionField()
  
      class Meta:
          unique_together = [("hostname", "ip_address")]
  
new_contents: """
  Modoboa API models.
  """
  from django.db import models
  
  from versionfield import VersionField
  
  
  class ModoboaInstance(models.Model):
  
      """
      A model to represent a modoboa instance.
      """
  
      hostname = models.CharField(max_length=255)
      ip_address = models.IPAddressField()
      known_version = VersionField()
  
      class Meta:
          unique_together = [("hostname", "ip_address")]
  
      def __str__(self):
          return "[{0}] {1} -> {2}".format(
              self.ip_address, self.hostname, self.known_version)
  
subject: Enhance instance display.