How to use function from model in CBV view?

Question

Django

I want to use the approv() method in order to add to the order the executor who left a review for a specific order, through which form or in what way can this be done on the order_detail.html page?

class Order(models.Model):
customer = models.ForeignKey(Customer,
                            related_name='orders',
                            on_delete=models.CASCADE)
title = models.CharField(max_length=250)
text = models.TextField()
image = models.ImageField(upload_to='orders/%Y/%m/%d',
                            blank=True)
price = models.DecimalField(max_digits=10, decimal_places=2)
executer = models.ForeignKey(Executer,
                            related_name='orders',
                            on_delete=models.SET_NULL,
                            blank=True,
                            null=True)
condition = models.BooleanField(default=False)
condition_success = models.BooleanField(default=False)
moderation = models.BooleanField(default=False)
slug = models.SlugField()

def __str__(self):
    return self.title

<b>def approv(self, executer_app):
    self.executer = executer_app
    self.condition = True
    self.save()</b>

def save(self, *args, **kwargs):
    if not self.slug:
        self.slug = slugify(self.title)
    super(Order, self).save(*args, **kwargs)

class ResponseOrder(models.Model):
    title = models.CharField(max_length=250)
    order = models.ForeignKey(Order,
                              related_name='responses_orders',
                              on_delete=models.CASCADE)
    executer = models.ForeignKey(Executer,
                                 related_name='responses_orders',
                                 on_delete=models.CASCADE)
    created = models.DateTimeField(auto_now_add=True)
    condition = models.BooleanField(default=False)

def __str__(self):
    return self.title


class AbstractProfile(models.Model):
    user = models.ForeignKey(User,
                             related_name='%(class)s_related',
                             on_delete=models.CASCADE)
    first_name = models.CharField(max_length=70)
    last_name = models.CharField(max_length=70)
    phone = PhoneNumberField(blank=True, unique=True)
    email = models.EmailField(unique=True)
    created = models.DateTimeField(auto_now_add=True)
    slug = models.SlugField()

class Meta:
    abstract = True

def __str__(self):
    return "{} {}".format(self.first_name,
                           self.last_name)

def save(self, *args, **kwargs):
    if not self.slug:
        self.slug = slugify(self.user.username)
    super(AbstractProfile, self).save(*args, **kwargs)

class Customer(AbstractProfile):
        pass

class Executer(AbstractProfile):
    description = models.CharField(max_length=250)

Views.

class OrderDetailView(FormMixin, DetailView):
    model = Order
    context_object_name = 'order'
    template_name = 'orders/manage/order/order_detail.html'
    form_class = ResponseForm
def get_success_url(self):
   return reverse('order:order_detail', kwargs={'pk': self.object.pk})

def get_context_data(self, **kwargs):
    context = super(OrderDetailView, self).get_context_data(**kwargs)
    context['responses'] = ResponseOrder.objects.filter(order=self.object)
    context['form'] = self.get_form()
    return context

def post(self, request, *args, **kwargs):
    if not request.user.is_authenticated:
        return HttpResponseForbidden()
    self.object = self.get_object()
    form = self.get_form()
    if form.is_valid():
        return self.form_valid(form)
    else:
        return self.form_invalid(form)

def form_valid(self, form):
    form.instance.executer = Executer.objects.get(user=self.request.user)
    form.instance.order = self.object
    form.save()
    return super(OrderDetailView, self).form_valid(form)

class OrderListView(ListView):
    model = Order
    context_object_name = 'orders'
    template_name = 'orders/manage/order/order_list.html'

class OrderCreateView(CreateView):
    model = Order
    fields = ['title', 'text', 'image', 'price']
    success_url = '/'
    template_name = 'orders/manage/order/order_create.html'
def form_valid(self, form):
    # customer =
    form.instance.customer = Customer.objects.get(user=self.request.user)
    return super().form_valid(form)

order_detail.html

<h3>{{ order.title }}</h3>
<form class=""  method="post">{% csrf_token %}
  {{form.as_p}}
  <input type="submit" name="" value="Отправить">
</form>
<hr>
<input type="submit" name="" value="">
{% for response in responses%}
{{response}}
<br>
{% endfor %}