def METHOD_NAME(self, request, *args, **kwargs):
    "Return usage for Prefix.pk == pk"
    pk = kwargs.pop("pk", None)
    prefix = Prefix.objects.get(pk=pk)
    max_addr = IP(prefix.net_address).len()
    active_addr = prefix_collector.collect_active_ip(prefix)
    # calculate allocated ratio
    query = PrefixQuerysetBuilder().within(prefix.net_address)
    allocated = query.finalize().exclude(vlan__net_type="scope")
    total_allocated = sum(p.get_prefix_size() for p in allocated)
    payload = {
        "max_addr": max_addr,
        "active_addr": active_addr,
        "usage": 1.0 * active_addr / max_addr,
        "allocated": 1.0 * total_allocated / max_addr,
        "pk": pk,
    }
    return Response(payload, status=status.HTTP_200_OK)