The procedure outlined in RCW 87.03.165 through 87.03.190, 87.03.200, and in 87.03.210, for the authorization, issuance and disposal of bonds as heretofore constituted and shall hereafter constitute a method independent and exclusive of that provided by any other statute or statutes, for the authorization, issuance and disposal of bonds of the district for any and all of the objects and purposes in said sections provided, and any or all proceedings heretofore had, official acts heretofore performed or any bonds heretofore authorized or issued or disposed of in substantial accordance with the provisions of said sections are hereby validated and confirmed.