Section 702 - Assistant district attorneys1. The board of supervisors shall have power to authorize the district attorney to appoint one or more assistant district attorneys. Every such appointment shall be in a writing filed and recorded in the office of the county clerk. The person appointed shall take the prescribed oath of office and furnish any required official undertaking. Any appointment may be revoked at any time by the district attorney by filing a written revocation in the office of the county clerk.2. The assistant shall perform such duties pertaining to the office as may be directed by the district attorney.3. The assistant during the absence or inability of the district attorney shall perform the powers and duties of the office of district attorney.4. In the event that more than one assistant is appointed, the district attorney shall designate in writing and file in the office of the county clerk and clerk of the board of supervisors the order in which such assistants shall exercise the powers and duties of the office in the event of a vacancy or the absence or inability of such district attorney to perform the duties of the office.5. In the event of a vacancy in the office of district attorney, the assistant, or if more than one has been appointed, the assistant so designated, shall perform the powers and duties of the office of district attorney until a successor is appointed and has qualified.6. Notwithstanding any provision of law with respect to requirements of residence, a district attorney of a county within a city having a population of one million or more may appoint one or more assistant district attorneys who are not residents of such county, but who reside within the geographical territory of such city.7. Notwithstanding any provision of law with respect to the requirements of residence, a district attorney may appoint one or more attorneys employed by the department of taxation and finance as special assistant district attorneys with respect to any investigation or prosecution concerning, in whole or part, a violation of article thirty-seven of the tax law or of the penal law as it applies to the enforcement of any provision of the tax law.