Premise: "Pirate Jenny" (German: "Seeräuber-Jenny ") is a well-known song from "The Threepenny Opera" by Kurt Weill, with lyrics by Bertolt Brecht. The English lyrics are by Marc Blitzstein. It is probably the second most famous song in the opera, after "Mack the Knife".
Hypothesis: Mack the Knife was not written by Kurt Weill