(a) Bonds issued by a district must be submitted to the attorney general for examination.
(b) If the attorney general finds that the bonds have been authorized in accordance with law, the attorney general shall approve them, and they shall be registered by the comptroller of public accounts.

(c) After the approval and registration of bonds, the bonds are incontestable in any court or other forum, for any reason, and are valid and binding obligations in accordance with their terms for all purposes.