Any or all of the attesting witnesses to any will may, at the request of the testator or, after his decease, at the request of the executor or any person interested under it, make and sign an affidavit before any officer authorized to administer oaths in or out of this state, stating such facts as they would be required to testify to in court to prove such will. The affidavit shall be written on such will or, if that is impracticable, on some paper attached thereto. The sworn statement of any such witness so taken shall be accepted by the Court of Probate as if it had been taken before such court.