Gifts to an attesting witness or his or her wife or husband, to be void

(1) Where any person attests the execution of any will to whom or to whose wife or husband any beneficial devise, legacy, estate, interest, gift or appointment of or affecting any real or personal estate, (other than and except charges and directions for the payment of any debt or debts) is thereby 11 given or made, such devise, legacy, estate, interest, gift or appointment shall, so far only as concerns such person attesting the execution of such will, or the wife or husband of such person or any person claiming under such person or wife or husband, be utterly null and void. (2) The person so attesting shall be admitted as a witness to prove the execution of such will or to prove the validity or invalidity thereof, notwithstanding such devise, legacy, estate, interest, gift or appointment mentioned in such will.