code: def question_default_serializer(self, obj):
          
          if not obj:
              return None
          self.question_default_add_related_pks(obj)
          return dict((
              ('id', obj.id),
              ('question_text', obj.question_text),
              self.field_to_json('DateTime', 'pub_date', obj.pub_date),
              self.field_to_json(
                  'PKList', 'choices', model=Choice, pks=obj._choice_pks),
          ))
docs: Convert a Question to a cached instance representation.