No further sinking funds for the payment of debt shall be established by any city, town or district, but cities and towns shall contribute to every sinking fund established prior to May twenty-eighth, nineteen hundred and thirteen, and districts shall contribute to every sinking fund established prior to March twentieth, nineteen hundred and fifteen, until such sinking fund, with its accumulations, shall be sufficient to extinguish at maturity the debt for which it was established. This section shall not apply to Boston.
Massachusetts Legal Code