Treaties — Parties — Whether territorial unit within a State can be party to a treaty — Extradition agreement between State and subordinate territory — Hong Kong — Hong Kong-United States of America Agreement for the Surrender of Fugitive Offenders, 1996 (“Hong Kong Extradition Agreement”) — United States Federal Extradition Statute — Whether Hong Kong Extradition Agreement a “treaty” between the United States and a “foreign government” within the meaning of the Federal Extradition Statute — The law of the United States of America