etcdctl member promote 8e9e05c52164694d No help topic for 'promote'/ flag provided but not defined: -learner

Why is there inaccurate information on the official website? Why do I use the syntax specified in the off documentation, and it tells me that the syntax is incorrect?
When i use etcdctl member add infra4 --peer-urls=http://10.0.1.14:2380 --learne. i get an error " flag provided but not defined: -learner"
After i used etcdctl member add node_name, i get error #0: client: etcd member http://192.168.12.131:2379 has no leader.
etcdctl memner list
client: etcd cluster is unavailable or misconfigured; error #0: client: endpoint http://127.0.0.1:2379 exceeded header timeout
; error #1: dial tcp 127.0.0.1:4001: connect: connection refused
But after i used this commands( member add), it loked like
etcdctl member list
8e9e05c52164694d: name=pg_node3 peerURLs=http://localhost:2380 clientURLs=http://192.168.12.133:2379 isLeader=true