How can I validate form when `CreateWithInlinesView` from the Django Extra Views is used?

def clean(self) and def clean_name_of_the_field methods don't work there. I have checked it on function based view , so that they really don't work in CreateWithInlinesView. I could still use validators and def clean() in model, but I would prefer to do it in forms...

This can be done in the views.
I found a solution here

class ModelCreate(CreateWithInlinesView):
    model = models.Model
    inlines = [ModelInline]
    form_class = forms.ModelForm
    success_url = reverse_lazy("app:related_name")

    def forms_valid(self, form, inlines):
        self.object = form.save()
        """Write your extra code in here"""
        return HttpResponseRedirect(self.get_success_url())