def book_update(request, pk):
    book = get_object_or_404(Book, pk=pk)
    form = BookForm(request.POST or None, instance=book)
    if form.is_valid():
        form.save()
        return redirect("index")
    return render(request, "book_edit.html", {"form": form})
def book_create(request):
    form = BookForm(request.POST or None)
    if form.is_valid():
        form.save()
        return redirect("index")
    return render(request, "book_create.html", {"form": form})