def sample(self):
        return {self.value: self.distribution.sample()}
test eager loading of a mapper which is against a select
dataset/ETHPy150Open sympy/sympy/sympy/stats/drv.py/SingleDiscretePSpace.sample--crossover with--dataset/ETHPy150Open zzzeek/sqlalchemy/test/orm/test_eager_relations.py/EagerTest.test_against_select