the Secretary of Transportation, with respect to any air carrier or foreign air carrier subject to that part. (4) Under the Packers and Stockyards Act, 1921 ( 7 U.S.C. 181 et seq.) (except as provided in section 406 of that Act ( 7 U.S.C. 226 , 227)) by the Secretary of Agriculture, with respect to any activities subject to that Act. (5) Under the Farm Credit Act of 1971 ( 12 U.S.C. 2001 et seq.) by the Farm Credit Administration, with respect to any Federal land bank, Federal land bank association, Federal intermediate credit bank, or production credit association. (c) Relation to private agreements It shall be unlawful for any covered entity to commit an act prohibited under this Act or a regulation promulgated under this Act, regardless of any specific agreement between entities or individuals. (d) No waiver of rights and remedies The rights and remedies provided under this Act may not be waived or limited by contract or otherwise. 16. State enforcement (a) In general In any case in which the attorney general of a State has reason to believe that an interest of the residents of that State has been or is threatened or adversely affected by the engagement of any covered entity in a practice that violates this Act or a regulation promulgated under this Act, the attorney general of the State may, as parens patriae, bring a civil action on behalf of the residents of the State in an appropriate district court of the United States to— (1) enjoin that practice