In counties of the first class of this Commonwealth, the expenditures of which are defrayed from the funds of any city within such counties by appropriation of the council of such city, all the powers, duties, and obligations with respect to this act and hereinbefore required or authorized to be performed or exercised by the county commissioners and board of control shall devolve upon and be exercised and performed by such city by and through its council and its appropriate executive officials in accordance with their respective duties and functions: Provided, That this section shall not invalidate any action or proceeding heretofore had or taken in such counties for the carrying out of the provisions of this act.
53 P.S. § 13628