@Override
        public Optional<MemberShape> getMember(String memberName) {
            if ("key".equals(memberName)) {
                return Optional.ofNullable(key);
            } else if ("value".equals(memberName)) {
                return Optional.ofNullable(value);
            } else {
                return Optional.empty();
            }
        }
Builder used to create a {@link ListShape}.
smithy-model/src/main/java/software/amazon/smithy/model/shapes/MapShape.java