. . .retailer's Class A license authorizes the holder to keep for sale and to sell, at the place described, beverages at retail and to deliver the beverages in a sealed package or container, which package or container shall not be opened nor its contents consumed on the premises where sold. The holder of a Class A license, if other than a person entitled to retail, compound, and dispense medicines and poisons, shall not on the licensed premises engage in any other business, keep for sale or sell any goods, wares, merchandise or any other article or thing except the beverages authorized under this license and nonalcoholic beverages.