The National Labor Relations Act imposes upon unions, as exclusive representative, a general duty to represent all members of the bargaining unit fairly. In addition to the civil rights laws, the union violates its duty of fair representation by discriminating on the basis of race, color, religion, sex, national origin, disability or age when acting in it s representative capacity. The duty of fair representation also requires that the union register its opposition to, and attempt to eradicate, any discriminatory practices which come within the scope of its collective bargaining agreement or negotiating powers.