The provisions of sections 15-269 to 15-276 and of any ordinance authorizing the issuance of bonds under such sections shall constitute a contract with the holders of such bonds, and any holder of a bond or bonds or any of the coupons of any bond or bonds of such city of the primary class, issued under sections 15-269 to 15-276, may either in law or in equity, by suit, action, mandamus, or other proceedings, enforce and compel the performance of all duties required by such sections or by the ordinance authorizing the bonds, including the making and collection of sufficient charges and fees for service and the use thereof, and the application of income and revenue thereof.
Neb. Rev. Stat. §§ 15-274