How to get the ID of the last created object added by newforms

def product_add(request):
    ProductForm = forms.form_for_model(Product)
    if request.method == 'POST':
        pf = ProductForm(request.POST.copy())
        if pf.is_valid():
            product = pf.save()
            return HttpResponseRedirect('/warehouse/products/%i/' % product.id)
    else:
        pf = ProductForm()
    return render_to_response(
        'warehouse/product_add.html',
        {'form': pf.as_table()})