Question: "Purple Rain-Union" is the sixth episode of the fourth season of the animated comedy series "Bob's Burgers", it aired on Fox in the United States on which date, the title of the episode is a reference to the song, film, and album "Purple Rain" by Prince?
Sentence (from "Purple Rain-Union"): "Purple Rain-Union" is the sixth episode of the fourth season of the animated comedy series "Bob's Burgers" and the overall 51st episode, and is written by Loren Bouchard and Nora Smith and directed by Tyree Dillihay.
Relevant evidence: No