It shall be proper to provide with respect to any bonds now required to be amortized as provided by *RCW
39.44.010 through
39.44.080, that such amortized annual maturities shall commence to be payable at any time on or before five years from the date of said bonds, and that any bonds, or any part thereof, issued under the authority of this chapter, shall be redeemable prior to their fixed maturities, as provided by the governing board or authority of any such issuer.