django获取choices的显示值

1,models.py

#订单表
class Orders(models.Model):
    status_cat = (
        ('0', '待装货'),
        ('1', '正在运输'),
        ('2', '已到达目的地'),
    )
    orders_status = (
        ('0', '待接单'),
        ('1', '已完成'),
    )
    order_num = models.CharField(max_length=255,verbose_name='订单编号')
    order_car = models.CharField(max_length=255,verbose_name='运输车辆')
    o_price = models.DecimalField(max_digits=10, decimal_places=2,verbose_name='总价')
    o_status = models.IntegerField(default=0,verbose_name='运输状态',choices=status_cat)
    order_status = models.IntegerField(default=0,verbose_name='订单状态',choices=orders_status)
    s_user_type = models.IntegerField(verbose_name='所属货主')    # 所属App_Client_User 
    o_user_type = models.IntegerField(verbose_name='所属车主')    # 所属App_Client_User 

2.serializers.py

class OrdersSerializers(serializers.ModelSerializer):
    #定义内置类  
    class Meta:
        #指定序列化的字段
        model = Orders
        #取所有的字段
        fields = "__all__"

    o_status = serializers.SerializerMethodField()
    def get_o_status(self,row):
        if row.o_status == 0:
            status = '待装货'
            return status
        elif row.o_status == 1:
            status = '正在运输'
            return status
        elif row.o_status == 2:
            status = '已到达目的地'
            return status
    
    order_status = serializers.SerializerMethodField()
    def get_order_status(self,row):
        if row.order_status == 0:
            status = '待接单'
            return status
        elif row.order_status == 1:
            status = '已完成'
            return status

3.views.py

#我的货单
class My_orders(APIView):
    def post(self,request):
        data = {}
        try:
            ret = request.POST.get("token")
            ret = jwt.decode(ret,'secret_key',algorithms=['HS256'])
            result = App_Client_User.objects.get(u_phone=ret['u_name'])
            if result.user_type == 8:
                data['code'] = StatusEnum.SUCCESS.value
                data['mes'] = CodeEnum.SUCCESS.value
                res = Orders.objects.filter(s_user_type = result.id)
                ser = serializers.OrdersSerializers(many=True,instance=res)
                data['data'] = ser.data
                return JsonResponse(data)
            else:
                data['code'] = StatusEnum.SUCCESS.value
                data['mes'] = '您不是货主'
                return JsonResponse(data)
        except:
            data['code'] = StatusEnum.FAIL.value
            data['mes'] = CodeEnum.FAIL.value
            return JsonResponse(data)

结果：

{
    "code": 200,
    "mes": "成功",
    "data": [
        {
            "id": 1,
            "o_status": "待装货",
            "order_status": "待接单",
            "order_num": "k20190918",
            "order_car": "宁A8888",
            "o_price": "50000.00",
            "s_user_type": 9,
            "o_user_type": 6
        },
        {
            "id": 2,
            "o_status": "正在运输",
            "order_status": "已完成",
            "order_num": "k20190912",
            "order_car": "宁A9999",
            "o_price": "100000.00",
            "s_user_type": 9,
            "o_user_type": 6
        }
    ]
}