Sinking funds of city; investment in warrants; limitation; direction to treasurer

The city council of any incorporated city of this state may make similar provision for the taking up of warrants out of the sinking funds in the hands of the city treasurer of such city. The warrants to be so purchased shall be limited to those of its own issue or to those of any school district situated mainly or wholly within the boundaries of such city. Upon a notice given of such direction it shall be the duty of such treasurer to so take up such warrants.