ip-nexthop does not support flush by id

Hi,

I use iproute-5.10 with kernel-5.10.6, I found that ip-nexthop does not support flush by id, is it by design?

Reproduce steps:
# ip netns add me
# ip -netns me addr add 127.0.0.1/8 dev lo
# ip -netns me link set lo up
# ip -netns me nexthop add id 105 blackhole proto 99
# ip -netns me nexthop flush id 105
id 105 blackhole proto 99
# ip -netns me nexthop ls
id 105 blackhole proto 99

while use flush without any args, flush will success.
# ip -netns me nexthop flush
Flushed 1 nexthops

I find the function ipnh_list_flush implemented in ipnexthop.c:

else if (!strcmp(*argv, "id")) {
			__u32 id;

			NEXT_ARG();
			if (get_unsigned(&id, *argv, 0))
				invarg("invalid id value", *argv);
			return ipnh_get_id(id);
		} 

When args is “id”, just return the related info of “id”, so I want to known is it by design ?