def add_art_view(request, pk, template_name='invstock/art_form.html'):
    id = get_object_or_404(Stock, pk=pk)
    form = StockForm(request.POST or None, instance=id)

    context = {
        'form': form
    }

    if form.is_valid():
        form.save()
        messages.success(request, ('Register Edited Successfully'))
        return redirect('invstock:art_list_view')

    return render(request, template_name, context)

{% extends "base.html" %}

{% block content %}
    {% if user.is_authenticated %}
        <h2><a href="{% url 'invstock:art_list_view' %}">ART FORM</a></h2>
            <form method="post">{% csrf_token %}
                 <div class="form-group">
                     <label>Cantidad</label>{{ form.cantidad}}
                     <label>Cantidad a debitar</label>{{ form.var_resta}}
                     <label>Name</label>{{ form.name}}
                     <label>ID</label>{{ form.id}}
                 </div>

                 <input type="submit" value="Submit" />
            </form>

{% endblock %}