Section 111B. Any foreman, laborer, workman or mechanic regularly employed by any city or town which accepts this section shall, when entitled thereto, be granted sick leaves aggregating not more than fifteen days in any year, exclusive of Sundays and holidays, without loss of pay; provided, that sick leave allowances not used in any particular year may be accumulated, for such number of years as may be determined by the city council of any such city or selectmen of any such town, for use in any subsequent year. The attorney general shall enforce this section, and shall have all necessary powers therefor.