private void assertIsListMember(String shapeName, MemberModel member) {
        if (!member.isList()) {
            throw new IllegalStateException(
                    String.format("Member %s from shape %s must be a list", member.getC2jName(), shapeName));
        }
    }
Verify the shape exists and the members provided exist and also verify the members
are list shapes.
aws-java-sdk-code-generator/src/main/java/com/amazonaws/codegen/customization/processors/SendEmptyAutoConstructedListAsEmptyListProcessor.java