§ 716. Public defender; appointment; term; other employees. The board of supervisors of any county may create an office of public defender, or may authorize a contract between its county and one or more other such counties to create an office of public defender to serve such counties. A city may create an office of public defender in any county wholly contained within its borders and such city shall possess with respect to such office all the powers conferred upon a board of supervisors by the provisions of this article. The board or boards of supervisors may designate an attorney-at-law as public defender and shall fix his term and compensation. Subject to the approval of such board or boards, the public defender may appoint as many assistant attorneys, clerks, investigators, stenographers and other employees as he may deem necessary and as shall be authorized by such board or boards. The public defender shall fix the compensation of such aides and assistants within the amounts such board or boards may appropriate for such purposes. Notwithstanding any other provision of law relating to the creation of county offices, where the board of supervisors of any county has established an office of public defender by resolution, and thereafter such office is created by local law, such local law may authorize the payment of compensation and other expenses incurred in the operation of said office retroactive to the date of the adoption of said resolution.