If a person attests the execution of a will, to whom or to whose spouse, or parent, or child, a devise or legacy is given by such will, such devise or legacy shall, so far only as concerns such person, or spouse, or parent, or child of such person, or any one claiming under such person or spouse, or parent, or child, be void, unless there are three other competent witnesses to such will. However, such person so attesting shall be admitted as a witness as if such devise or legacy had not been made or given. (n)