AppleMusic / Spotify demo project in Swift

Your job is to create a Swift 5 (iOS 13) demo project (proof of concept) that will allow the user to login to Apple Music and to Spotify. The user will then be able to choose from his existing playlists and start playing the tracks of the playlist consecutively. The app will show standard play controls (play / pause / track skip). The app should also feature an additional button (in addition to the standard music playback control) that will play a sound file "on top" of the AppleMusic/Spotify track (so the sound file and the music track can be heard simultaneously). There should also be a slider control to select the amount of "ducking" i.e. how much should the volume level of the AppleMusic/Spotify track be decreased when playing the sound file. 0% ducking = music track volume will remain the same while the sound effect will be played at the same volume level - 100% ducking = music track will not be heard while the sound effect is playing This app does not have any other UI elements. It is NOT supposed to be put into a store. This is just a proof concept and it needs to work on iOS 13. You need to have an AppleID with AppleMusic subscription in order to be awarded for the project. In case you don't also have a Spotify premium account (as it's needed for this as well) you will be getting temporary credentials to an existing Spotify premium account. *IMPORTANT* Please make sure share a list (with links) of your previous Swift projects for reference and what kind of iPhone you have and what MacOS and Xcode version you are currently running. If you fail to mention this then it is obvious that you have not read and understood the full project description and your bid will be disregarded.