The mayor, at least once a year, shall appoint a certified public accountant or the Department of Examiners of Public Accounts to conduct an examination in accordance with generally accepted auditing standards of all books and accounts of the city since the preceding examination and to make a full report thereof in writing, under oath, to be submitted to the council at its first meeting after the completion of such report, and the same shall be spread upon the minutes of the council. For his services, said certified public accountant or the Department of Examiners of Public Accounts shall be paid such sum as may be agreed upon.