“Officer” and “public officer” means a person holding office under a city, county, or state government or the federal government who performs a public function and in so doing is vested with the exercise of some sovereign power of government and includes all assistants, deputies, clerks and employees of any public officer and all persons lawfully exercising or assuming to exercise any of the powers or functions of a public officer. (Ord. 1145-85 § 14(12), 1985.)