(a) The debt service fund shall not be used for any other purpose in any year than to pay the bonds and interest thereon maturing that year and any that may be past due, until the maturities are paid in full or until the funds are set aside to pay the full amount of the bonds; provided, the surplus in any year over and above the amount necessary to pay bonds and interest maturing that year, whether hereafter or heretofore issued, may be used by the respective school districts for any other school purposes.
(b) The county treasurer, or school district treasurer if the school district has its own treasurer, shall see to it that all warrants on the debt service fund of any school district are drawn only to pay maturities of principal or interest on bonds of this school district, other school purposes as herein provided, or past due interest as shown by the records in his or her office.
(c) It is intended that the provisions of this section are to be cumulative and are not to repeal the provisions of any other act now in force except such laws and parts of laws as may be in conflict herewith.