How do I get the lyrics of the currently playing s

问题:

I am getting the Current Song playing as an MPMediaItem and I can successfully retrieve the title, artist and song length. However when I try to get the lyrics nothing shows up in the text field that I am updating.

let currentSong: MPMediaItem = mediaItemCollection.items[0]

if let artwork: MPMediaItemArtwork = currentSong.value(forProperty: MPMediaItemPropertyArtwork) as? MPMediaItemArtwork {
    albumArtwork.image = artwork.image(at: CGSize(width: 120, height: 120))
    songTitle.text = currentSong.title
    songArtist.text = currentSong.artist
    songLength.text = currentSong.playbackDuration.stringFromTimeInterval()
    songLyrics.text = currentSong.lyrics

}

I want songLyrics.text to be equal to the lyrics of the song.