“Employment” does not include service performed by a person as a caddy at a golf course in an established program for the training and supervision of caddies under the direction of a person who is an employee of the golf course. However, the provisions of this section do not apply to services performed for:
(1) A nonprofit employing unit;
(2) This state;
(3) A political subdivision of this state; or
(4) An Indian tribe. [1993 c.494 §4; 2001 c.572 §2; 2005 c.218 §8]