9.—(1) Upon the discharge by a person assessed to the levy of his liability under an assessment the Board shall if so requested issue to him a certificate to that effect.
(2) The production in any proceedings of a document purporting to be certified by the Secretary of the Board to be a true copy of an assessment or other notice issued by the Board or purporting to be a certificate such as is mentioned in the foregoing paragraph of this Article shall, unless the contrary is proved, be sufficient evidence of the document and of the facts stated therein.