Diplomatic relations — Diplomatic agents — Immunity from jurisdiction — Vienna Convention on Diplomatic Relations, 1961 — Article 31(1)(c) — Action by domestic servant alleging that she had been trafficked and forced to work by former employers — Certification of diplomatic status of former employers — Whether diplomatic immunity continuing despite subsequent termination of diplomatic status — Whether commercial activity exception applicable to hiring of domestic servant — Whether subsequent attempts at service defective — Whether Court lacking jurisdiction — The law of the United States