Notwithstanding sections 952, 953, and 957 of this title—
((1)) A controlled substance in schedule I may—
((A)) be imported into the United States for transshipment to another country, or
((B)) be transferred or transshipped from one vessel, vehicle, or aircraft to another vessel, vehicle, or aircraft within the United States for immediate exportation,
((2)) A controlled substance in schedule II, III, or IV may be so imported, transferred, or transshipped if and only if advance notice is given to the Attorney General in accordance with regulations of the Attorney General.