  
  from django.core import management, serializers
  from django.core.serializers.base import DeserializationError
  from django.test import SimpleTestCase, TestCase, TransactionTestCase
  from django.utils import six
  from django.utils.six import StringIO
  
  from .models import Author
  from .tests import SerializersTestBase, SerializersTransactionTestBase
  
 
</s> remove from django.utils import six
 </s> add  </s> remove from django.utils import six
 </s> add  </s> remove from django.utils import six
 </s> add  </s> remove from django.utils import six
 </s> add  </s> remove from django.utils import six
 </s> add 
  
  from django.core import management, serializers
  from django.core.serializers.base import DeserializationError
  from django.test import SimpleTestCase, TestCase, TransactionTestCase

  from django.utils.six import StringIO
  
  from .models import Author
  from .tests import SerializersTestBase, SerializersTransactionTestBase
  
keep keep keep keep replace keep keep keep keep keep
 Refs #23919 -- Removed six.<various>_types usage

Thanks Tim Graham and Simon Charette for the reviews. 
tests/serializers/test_yaml.py