  
  from django.conf import settings
  from django.core.exceptions import ImproperlyConfigured
  from django.db.backends import utils
  from django.utils import six, timezone
  from django.utils.dateparse import parse_duration
  from django.utils.encoding import force_text
  
  
  class BaseDatabaseOperations(object):
 
</s> remove from django.utils import six, timezone
 </s> add from django.utils import timezone </s> remove from django.utils import six, timezone
 </s> add from django.utils import timezone </s> remove from django.utils import six, timezone
 </s> add from django.utils import timezone </s> remove from django.utils import six
 </s> add  </s> remove from django.utils import lru_cache, six
 </s> add from django.utils import lru_cache
from django.utils import timezone
  
  from django.conf import settings
  from django.core.exceptions import ImproperlyConfigured
  from django.db.backends import utils
from django.utils import timezone
  from django.utils.dateparse import parse_duration
  from django.utils.encoding import force_text
  
  
  class BaseDatabaseOperations(object):
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. 
django/db/backends/base/operations.py