Be it further enacted, That prior to the end of each fiscal year the council shall designate a certified public accountant or accountants who, as of the end of the fiscal year, shall make an independent audit of accounts and other evidences of financial transactions of the city government and shall submit their report to the council and to the city manager. Such accountant or accountants shall have no personal interest, direct or indirect in the fiscal affairs of the city government or of any of its officers. They shall not maintain any accounts or records of the city business, but, within specifications approved by the council, shall postaudit the books and documents kept by the department of finance and any separate or subordinate accounts kept by any other office, department, or agency of the city government.