(a) Any improvement district organized under the provisions of this chapter after February 1, 1967, may sell or lease its improvement, or any part thereof, to the city or town or to a public authority or other agency serving on behalf of the property owners of the district on such terms as the commissioners of the improvement board may deem for the best interest of the district and apply the proceeds therefrom on the payment of the principal of and interest on its outstanding bonds, if any, together with any paying agent's or other charges in connection therewith.
(b) The city or town within which the district is located is authorized to purchase or to lease as lessee and to operate the improvement of the district on such terms as it may agree with the commissioners.