Searches through all of the user's Spotify playlists for a particular song. It then returns the playlists that the song is within.
In order to use the source code, you'll need to make your own app on Spotify's Developer Dashboard. You'll then need to add three environment variables to your system provided by Spotify. The client id, the client secret, and the redirect uri. Spotipy's documentation provides a good tutorial if more information is needed to set this up.
Makes use of the Spotipy Library so thank you to the contributors there to allow this project to exist.