All offices and places of employment other than those specifically exempted by the provisions of section 13 of this Act, in any Park Employees' and Retirement Board Employees' Annuity and Benefit Fund System created under the provisions of Article 12 of the "Illinois Pension Code" as the same may from time to time be amended, shall be classified and filled in the manner hereinafter provided for and not otherwise.
70 ILCS 1215/1