SEC. 137. CONTRACTS FOR LIGHTING, HEATING AND POWER NOT TO EXCEED ONE YEAR'S DURATION; EXCEPTION AS TO CONTRACTS WITH OTHER MUNICIPAL CORPORATIONS.
   No contract for lighting streets, public buildings or offices or public places or for furnishing the city with heat or power shall be made for a longer period than one year, except that any such contract may be made with any other municipal corporation for a period not longer than ten years.