421.26 Notes and bonds.—All proceedings, acts and things heretofore undertaken, performed or done in or for the authorization, issuance, execution and delivery of notes and bonds by housing authorities for the purpose of financing or aiding in the development or construction of a housing project or projects, and all notes and bonds heretofore issued by housing authorities are hereby validated, ratified, confirmed, approved and declared legal in all respects, notwithstanding any defect or irregularity therein or any want of statutory authority.