. . . "Sec. 47.04. KEEPING A GAMBLING PLACE. (a) A person commits an offense if he knowingly uses or permits another to use as a gambling place any real estate, building, room, tent, vehicle, boat, or other property whatsoever owned by him or under his control, or rents or lets any such property with a view or expectation that it be so used.(b) It is an affirmative defense to prosecution under this s" . . .