Any municipality having surplus sinking funds under the provisions of Sections 57-1-1 through 57-1-51 may, in the discretion of the governing board of such municipality, invest said sinking funds by purchasing bonds of any county or municipality of this state, bonds of the State of Mississippi, or bonds issued by authority of the United States government, except drainage district bonds, provided, that the bonds so purchased shall mature prior to the time when the bonds payable out of the sinking fund hereunder shall fall due.