  from datetime import datetime
  
  from django.conf import settings
  from django.db.models import (
      DateField, DateTimeField, DurationField, IntegerField, TimeField,
      Transform,
  )
  from django.db.models.lookups import (
      YearExact, YearGt, YearGte, YearLt, YearLte,
  )
 
</s> remove from django.utils.functional import cached_property
 </s> add  </s> remove     @cached_property
    def output_field(self):
        return IntegerField()

 </s> add  </s> remove         output_field = copy.output_field
        explicit_output_field = field.__class__ != copy.output_field.__class__
 </s> add         class_output_field = self.__class__.output_field if isinstance(self.__class__.output_field, Field) else None
        output_field = class_output_field or copy.output_field
        has_explicit_output_field = class_output_field or field.__class__ is not copy.output_field.__class__ </s> remove                 field.name, output_field.__class__.__name__ if explicit_output_field else 'DateTimeField'
 </s> add                 field.name, output_field.__class__.__name__ if has_explicit_output_field else 'DateTimeField' </s> remove                 field.name, output_field.__class__.__name__ if explicit_output_field else 'DateTimeField'
 </s> add                 field.name, output_field.__class__.__name__ if has_explicit_output_field else 'DateTimeField'
    DateField, DateTimeField, DurationField, Field, IntegerField, TimeField,
  from datetime import datetime
  
  from django.conf import settings
  from django.db.models import (
    DateField, DateTimeField, DurationField, Field, IntegerField, TimeField,
      Transform,
  )
  from django.db.models.lookups import (
      YearExact, YearGt, YearGte, YearLt, YearLte,
  )
keep keep keep keep replace keep keep keep keep keep
 Fixed #28492 -- Defined default output_field of expressions at the class level.

This wasn't possible when settings were accessed during Field initialization
time as our test suite setup script was triggering imports of expressions
before settings were configured. 
django/db/models/functions/datetime.py