Whenever any school district shall heretofore have passed a resolution signifying its desire to increase its bonded indebtedness, and whenever the assent of a majority of the electorate of such district shall have been obtained at an election held within such district assenting to such increase in indebtedness, and whenever notice of such election shall have been given in the legal journal designated by rules of court for publication of legal notices and advertisements, and whenever the lawful number of notices shall have been posted within the district giving notice of such election, all bonds heretofore or hereafter issued pursuant to such election are hereby made valid and binding obligations of such school district notwithstanding the fact that notice of said election was not advertised in any newspaper published in or circulated generally throughout the district, as required by law: Provided, That all other requirements of law concerning the issuance of such bonds and the proceedings relative thereto shall have been complied with.