All deeds and conveyances of land executed by or purporting to be executed by a school district or by the board of directors of a school district, and placed of record more than ten years earlier, which deeds or conveyances purport to sustain the record title, are legalized and valid, even though the record fails to show that all necessary steps in the sale and deeding of the property were complied with. The deeds and conveyances are legalized and valid as if the record showed that the law had been complied with, and that the sales had been duly authorized by the electors of the school district.