The commission form of city government means a city government in which the legislative powers and duties are exercised by a commission of three, consisting of a mayor, a commissioner of finance and accounting, and a commissioner of streets and public improvements, and in which the executive and administrative powers and duties are distributed among the three departments as follows:
(1) Department of public safety of which the mayor shall be the superintendent;
(2) Department of finance and accounting of which the commissioner of finance and accounting shall be the superintendent;
(3) Department of streets and public improvements of which the commissioner of streets and public improvement shall be the superintendent.