无法使用 djangofilters 进行过滤

我有一张models.py，看起来像这样

class Product(models.Model):
    name = models.CharField(max_length = 255, unique = True, null = False, blank = False)
    brand = models.ForeignKey(Brand, on_delete = models.SET_NULL, null = True, blank = True, related_name = 'products')

class Brand(models.Model):
    name = models.CharField(max_length = 255, unique = True, null = False, blank = False)

我想过滤基于Brand型号的name字段的产品数据.我的views.py号是这样的

class ProductAPIView(generics.GenericAPIView):

    serializer_class = ProductSerializer
    queryset = Product.objects.all()
    filter_backends = (DjangoFilterBackend,)
    filterset_class = ProductFilter
    
    def get(self, request):
        products = self.filter_queryset(self.get_queryset())
        serializer = self.serializer_class(products, many = True)
        return Response(serializer.data)

我的filters.py是这样的

class ProductFilter(FilterSet):

    class Meta:
        model = Product
        fields = {
            'brand__name' : ['iexact', ]
        }

无论我为brand发送什么查询参数，结果都是整个列表，而不是过滤所需的列表. 我是不是漏掉了什么？提前谢谢你