; (4) by amending subsection (e) to read as follows: (e) Notwithstanding chapter 1 of title 9, United States Code (commonly known as the Federal Arbitration Act ), or any other provision of law, it shall be an unfair labor practice under subsection (a)(1) for any employer to enter into any contract or agreement, express or implied, whereby an employee of the employer undertakes or promises not to pursue, bring, join, litigate, or support any kind of collective legal claim arising from or relating to the employment of such employee in any forum that, but for such contract or agreement, is of competent jurisdiction. The provisions of this subsection shall not apply with respect to employees who are represented by a labor organization and covered by a collective-bargaining agreement in effect with the employer. Any contract or agreement entered into heretofore or hereafter containing an agreement prohibited by this subsection shall be to such extent unenforceable and void.