108.230.  Bond issue funds exempt from attachment and execution. — All money collected and all securities purchased or held belonging to the interest and sinking fund of any county, city, incorporated town or village, school district, or other political corporation or subdivision of the state shall be exempt from attachment and execution.  Such money and securities shall be exempt from being levied upon, taken, sequestered, or applied toward paying the debts of any such county, city, incorporated town or village, school district, or other political corporation or subdivision of the state, other than for payment of the indebtedness for which such funds and securities were provided.  The money and securities so held shall be deemed to be an inviolable sinking fund for the purpose of extinguishing the indebtedness for which such fund had been levied and collected.