def music_add(request, music_id=None):

    if music_id is not None:
        music = get_object_or_404(Music, pk=music_id)
    else:
        music = None

    if request.method == 'POST':
        form = MusicForm(request.POST, request.FILES, instance=music)
        if form.is_valid():
            music = form.save(commit=False)
            music.user = request.user
            music.save()
            form.save_m2m()
            messages.success(request, 'Salvo com sucesso!')
            return HttpResponseRedirect(reverse('repertory:musics_list'))
    else:
        form = MusicForm(instance=music)
    return render(request, 'repertory/music_add.html', {'form':form,})