对queryset.get进行优化,使其在模型的管理器中不出现doesonexist异常。

我有两个相似的模型,一个公共管理器,它为当前登录的用户返回查询集。我想要user_places.current_user.get(place=xxx)返回现有的user_place()对象或空的user_places(),当不出现texist异常时。怎么可能?如果我是对的,那么CurrentUserManager对用户位置和用户项目模型一无所知?

我只是不想总是写:

try:
    places = User_Places.current_user.get(place=XXX)
except:
    places = User_Places()

我的型号代码:

class User_Places(models.Model):
    place = models.ForeignKey('Place')
    user = models.ForeignKey(User)
    current_user = CurrentUserManager()

class User_Projects(models.Model):
    project = models.ForeignKey('Project')
    user = models.ForeignKey(User)
    current_user = CurrentUserManager()

class CurrentUserManager(models.Manager):
    def get_query_set(self):
        user = threadlocals.get_current_user()
        qs = super(CurrentUserManager, self).get_query_set()
        if user:
            qs = qs.filter(user=user)
        return qs

    def get(self, *args, **kwargs):
        try:
            object = super(CurrentUserManager, self).get(*args, **kwargs)
        except:
            object = ????????????????????????
        return object