playtrix

Hello! I am currently making a ressource pack for 1.15.x. I wanted to make it so that the model of the furnace changes depending on what is inside. I know that you can use predicates in resource packs to some extend but I don't know if and/or how I can check for a blocks BlockEntity properties, which according to my understanding should contain information, such as the content of the container's slots. If you know how I can do this or if it is even possible, please help! Thanks!