App\services\Download::from PHP Method

    public function from($mixed)
    {
        if (is_a($mixed, Song::class)) {
            return $this->fromSong($mixed);
        } elseif (is_a($mixed, Collection::class)) {
            return $this->fromMultipleSongs($mixed);
        } elseif (is_a($mixed, Album::class)) {
            return $this->fromAlbum($mixed);
        } elseif (is_a($mixed, Artist::class)) {
            return $this->fromArtist($mixed);
        } elseif (is_a($mixed, Playlist::class)) {
            return $this->fromPlaylist($mixed);
        } else {
            throw new Exception('Unsupport download type.');
        }
    }