78.(1) For the purposes of sections 76 and 77 no building, tenement or land shall be deemed vacant if maintained as a pleasure resort or town or country house, or be deemed unproductive of rent if let to a tenant who has a continuing right of occupation thereof, whether he is in actual occupation or not. (2) The burden of proving all facts entitling any person to claim relief under section 75, or section 76, or section 77, shall be upon him.