With the cops on their tail they cut through a messy warehouse with three burlap sacks. They each jump in a sack hoping to hide from the police who come busting into the warehouse. As the cops search a young rookie notices the sacks. As he’s a bit lazy (and more than a bit thick) he gives the first bag a kick, rather than search it. The robber in the sack panics and says “meow meow” to which the cop nods and says “huh, just a cat in the bag. Fair enough. But what’s in this next sack?” He gives it a kick and the robber inside goes “woof woof” to which the cop says “ahhh, this sack has dogs. Makes sense, keep the dogs and cats separate… But what have we in this third sack?!?” He gives it a kick and hears “potato potato potato.”
Makes more sense if you say the last one’s Irish.