If a final order be entered establishing the district, such order shall be deemed final and conclusive, and no appeal or writ of error shall lie therefrom, and the entry of such order shall finally and conclusively establish the regular organization of said district against all persons except the state of Missouri, in an action in the nature of a writ of quo warranto, commenced by the attorney general within thirty days after said decree declaring such district finally organized as herein provided and not otherwise. The organization of such district shall not be directly or collaterally questioned in any suit, action or proceeding except as herein expressly authorized.
§ 321.140, RSMo