django orm按某个字段分类

class Example(models.Model):
    types = models.CharField(choices=Choice('A', 'B', 'C',  max_length=4)

{ 
    'A' : [ExampleObject(1), ExampleObject(3), ExampleObject(4)],
    'B' : [ExampleObject(2), ExampleObject(6)],
    'C' : [ExampleObject(5), ExampleObject(7), ExampleObject(8)]
}