(a) This chapter shall not diminish the obligation of an employer to comply with any contract, collective bargaining agreement, or any employment benefit program or plan that provides greater paid leave rights to employees than the rights established under this chapter. (b) The paid leave requirements under this chapter shall not be waived for less than 3 paid leave days per calendar year by the written terms of a bona fide collective bargaining agreement; provided, that the paid leave requirements under this chapter shall not apply to any employee in the building and construction industry covered by a bona fide collective bargaining agreement.