django - CASE WHEN

Client.objects.annotate(
    discount=Case(
        When(registered_on__lte=a_year_ago, then=Value('10%')),
        When(registered_on__lte=a_month_ago, then=Value('5%')),
        default=Value('0%'),
        output_field=CharField(),
    )
).values_list('name', 'discount')