(a) If the defendant shall not avail himself or herself of the right to testify or of the testimony of the wife or husband on the trial in the case, it shall not be construed to affect the innocence or the guilt of the defendant nor shall the same raise any presumption of guilt, nor be referred to by any party or attorney in the case, nor be considered by the court or jury before whom the trial takes place.

(b) If the defendant does not testify and the defendant so requests, but not otherwise, the court shall instruct the jury in writing as follows:

“Under the law, a defendant has the right not to testify. No presumption of guilt may be raised and no inference of any kind may be drawn from the fact that defendant did not testify.”