The board may submit any bonds issued under this article to the attorney general after all proceedings for their authorization have been completed. On submission the attorney general shall examine and pass on the validity of the bonds and the regularity of the proceedings. If the proceedings comply with this article, and if he determines that, when delivered and paid for, the bonds will constitute binding and legal obligations of the board, the attorney general shall certify on the back of each bond, in substance, that it is issued according to the constitution and laws of this state.