; and (2) may issue such rules as interim final rules. (b) Procedure for final rule A rule issued by the Attorney General as an interim final rule under subsection (a) shall become immediately effective as an interim final rule without requiring the Attorney General to demonstrate good cause therefor. The interim final rule shall give interested persons the opportunity to comment and to request a hearing. After the conclusion of such proceedings, the Attorney General shall issue a final rule in accordance with section 553 of title 5, United States Code. 9. GAO report (a) In general Not more than 4 years after the date of enactment of this Act, the Comptroller General of the United States shall submit to the Committees on Energy and Commerce and the Judiciary of the House of Representatives and the Committee on the Judiciary of the Senate a report analyzing the implementation and impact, to the extent information is available, of permanent class scheduling pursuant to schedule I(e) of section 202(c) of the Controlled Substances Act, as added by section 2 of this Act, of fentanyl-related substances (as defined in such schedule I(e)), which report shall include— (1) an analysis of the impact on research of fentanyl-related substances; (2) an analysis of any actions taken to remove or reschedule in a different class any fentanyl-related substance; (3) an analysis of the impact of permanent scheduling on the unlawful importation, manufacture, trafficking, and use of fentanyl-related substances, taking into consideration data collected concerning the proliferation of fentanyl-related substances since class scheduling was instituted; (4) an analysis of sentences attributable to criminal charges involving fentanyl-related substances, comparing those sentences to sentences attributable to criminal charges involving fentanyl and individually scheduled fentanyl analogues