Django-filter: Berisi / ikon filter tidak berfungsi

class OrderFilter(django_filters.FilterSet):
    class Meta:
        model = Order
        fields = {
            'status': ['exact',],
            'client': ['icontains',],
        }

class OrderViewset(viewsets.ModelViewSet):
    filter_class = OrderFilter
    permission_classes = ( permissions.IsAuthenticated, )
    serializer_class = OrderSerializer
    queryset = Order.objects.all()
    filter_backends = (
        filters.OrderingFilter,
        filters.SearchFilter,
        filters.DjangoFilterBackend
    )
    ordering_fields = ('added_at', 'status', 'client', 'order_number')
    ordering = ('-added_at',)

class Order(models.Model):
    order_number = models.CharField(max_length=255, default='')
    client = models.CharField(max_length=255, default='')
    status = models.CharField(max_length=255, default='')
    added_at = models.DateTimeField(auto_now_add=True)

Filter klien pada dasarnya diabaikan. Jika saya mengganti icontains dengan tepat, itu berfungsi.
Tapi saya tidak bisa mendapatkan berisi atau ikon untuk bekerja di bidang apa pun.

Persyaratan.txt:

Django==1.10.4
psycopg2==2.6.2
djangorestframework==3.5.3
saluran == 1.0.0
djangorestframework-jwt==1.9.0
django-filter == 1.0.1
asgi-redis==1.0.0
daphne==1.0.0