Whether one YANG module list without key is valid

I just want to confirm one question, whether the list without key is valid, please see the below example:

               list item {
                  choice item1 {
                    case item11 {
                      leaf item111 {
                        type string; }
                    case item2 {
                      leaf item22 {
                        type string;}
                  leaf a {
                    type string;


According to RFC 7950 key must be present only if list represents configuration. For operational data (config false) it can be left out. See example 8-c_stats_no_key.