I am try to extract the audio file url from Shazamkit, it is deep inside the hierarchy of SHMediaItem > songs > previewAssets > url when I access the url with like this: let url = firstItem.songs[0].previewAssets?[0].url I am getting a warning like this: here is the Variable Viewer this is what I have done so far: struct MediaItems: Codable { let title: String? let subtitle: String? let shazamId: String? let appleMusicId: String? let appleMusicUrL: URL? let artworkUrl: URL? let artist: String? let matchOffset: TimeInterval? let videoUrl: URL? let webUrl: URL? let genres: [String] let isrc: String? let songs: [Song]? } extension SwiftFlutterShazamKitPlugin: SHSessionDelegate{ public func session(_ session: SHSession, didFind match: SHMatch) { let mediaItems = match.mediaItems if let firstItem = mediaItems.first { // extracting the url let url = firstItem.songs[0].previewAssets?[0].url let _shazamMedia = MediaItems( title:firstItem.title!, subtitle:firstItem.subtitle!, shazamId:firstItem.shazamID!, appleMusicId:firstItem.appleMusicID!, appleMusicUrL:firstItem.appleMusicURL!, artworkUrl:firstItem.artworkURL!, artist:firstItem.artist!, matchOffset:firstItem.matchOffset, videoUrl:firstItem.videoURL!, webUrl:firstItem.webURL!, genres:firstItem.genres, isrc:firstItem.isrc!, songs:firstItem.songs ) do { let jsonData = try JSONEncoder().encode([_shazamMedia]) let jsonString = String(data: jsonData, encoding: .utf8)! self.callbackChannel?.invokeMethod("matchFound", arguments: jsonString) } catch { callbackChannel?.invokeMethod("didHasError", arguments: "Error when trying to format data, please try again") } } }