b. Upon the effective date of this article, the office of constable serving magistrate courts is abolished. The functions, powers and duties of such constables shall be transferred to and be performed by the sheriff of the county or the sheriff of the city of St. Louis.
The general assembly shall not pass any local or special law:
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(21) creating offices, prescribing the powers and duties of officers in, or regulating the affairs of counties, cities, townships, election or school districts;