As used in this subchapter, unless the context otherwise requires, “public servant” means:
(1) Any officer or employee of this state or of any political subdivision thereof;
(2) Any person exercising the functions of any such officer or employee;
(3) Any person acting as an advisor, consultant, or otherwise in performing any governmental function, but not including witnesses; or
(4) Any person elected, appointed, or otherwise designated to become a public servant, although not yet occupying that position.