3Proof of instrument to validity of which attestation is necessary.N.I.
Subject as hereafter in this section provided, in any proceedings, whether civil or criminal, an instrument to the validity of which attestation is requisite may, instead of being proved by an attesting witness, be proved in the manner in which it might be proved if no attesting witness were alive:
Provided that nothing in this section shall apply to the proof of wills or other testamentary documents.