def latest(self, column='created_at'):
        return self.order_by(column, 'desc')
1. map only subclass of class
dataset/ETHPy150Open sdispater/orator/orator/query/builder.py/QueryBuilder.latest--crossover with--dataset/ETHPy150Open zzzeek/sqlalchemy/test/orm/test_events.py/DeferredMapperEventsTest.test_deferred_map_event_subclass_post_mapping_propagate_two