@Override
        public boolean contains(Object key) {
            // try the backing map
            if (this.backing.contains(key)) {
                return true;
            }

            // then try the permissible
            if (key instanceof Permissible) {
                Permissible p = (Permissible) key;
                return p.hasPermission(this.permission);
            }

            // no result
            return false;
        }
Value map extension which includes LP objects in Permissible related queries.
nukkit/src/main/java/me/lucko/luckperms/nukkit/inject/server/LuckPermsSubscriptionMap.java