def move_dates(apps, schema_editor):
    """Move dates to models."""
    Domain = apps.get_model('admin', 'Domain')
    DomainAlias = apps.get_model('admin', 'DomainAlias')
    Mailbox = apps.get_model('admin', 'Mailbox')
    Alias = apps.get_model('admin', 'Alias')
    for model in [Domain, DomainAlias, Mailbox, Alias]:
        for instance in model.objects.all():
            instance.creation = instance.dates.creation
            instance.last_modification = instance.dates.last_modification
            instance.save()
