Show now playing song from spotify in tmux powerline on elementary linux

now_playing.sh

__np_spotify_elementary() {
        [ ! shell_is_linux ] && return 1
        spotify_ids=$(xwininfo -root -tree | grep '("spotify' | cut -f1 -d'"' | sed 's/ //g')
        for spotify_id in $spotify_ids
        do
                title=$(xwininfo -id "$spotify_id" | grep "xwininfo" | grep -Po "(?<=\").*(?=\"$)")
                if [ "$title" != "spotify" ]; then
                        echo $title
                fi
        done
}