The collective bargaining agreement between National Children's Center and SEIU Local 500 provides that, all employees who are members of the union of the effective date of the agreement or voluntarily join hereafter, shall maintain their membership or satisfy the financial obligations set by the Union, as a condition of continued employment. All employees covered by the agreement who are not members of the union shall within (31) calendar days after employment remain members or become agency-fee payers as a condition of continued employment.