; or (ii) a remedy would otherwise not be reasonably available or practicable. (6) Challenges to the validity of the system (A) In general Except as provided in paragraph (5), any claim that section 245B, 245C, 245D, 245E, 245F, or 245G, or any regulation, written policy, written directive, or issued or unwritten policy or practice initiated by or under the authority of the Secretary to implement such sections, violates the Constitution of the United States or is otherwise in violation of law is available in an action instituted in a district court of the United States in accordance with the procedures prescribed in this paragraph. (B) Savings provision Except as provided in subparagraph (C), nothing in subparagraph (A) may be construed to preclude an applicant under section 245B, 245C, 245D, 245E, or 245F from asserting that an action taken or a decision made by the Secretary with respect to the applicant’s status was contrary to law. (C) Class actions Any claim described in subparagraph (A) that is brought as a class action shall be brought in conformity with— (i) the Class Action Fairness Act of 2005 ( Public Law 109–2 ; 119 Stat. 4)