The indebtedness of a city or town for a specific purpose shall be its net indebtedness, which shall be the total indebtedness for that purpose after deducting the amount of sinking funds applicable to the same. The indebtedness to which the debt limit imposed by section ten shall be applied shall be the total net indebtedness of the city or town after excluding debts exempted from the operation of said section.
Mass. Gen. Laws ch. 44, § 3