我试图在一个表单中添加一些额外的验证，覆盖它的clean方法，但错误并没有引发，一个ValueError异常说“The view apps.orders.views.view didn't return an HttpResponse object.但是如果我在if条件中使用else子句来检查表单是否有效并打印form.errors，它会打印clean方法中创建的错误。为了记录，我使用的是表单沿着表单集。先谢了。
下面是表格：

class OrderForm(forms.ModelForm):
    """ModelForm Class for Orders objects."""
    class Meta:
        model = Order
        fields = '__all__'
        widgets = {
            'executor_signature_date': forms.DateInput(
                format=('%Y-%m-%d'),
                ),
            'customer_signature_date': forms.DateInput(
                format=('%Y-%m-%d'),
                ),
        }
    
    def clean(self):
        cleaned_data = super().clean()
        check_diagnosis = cleaned_data.get("check_diagnosis")
        repair = cleaned_data.get("repair")
        install = cleaned_data.get("install")
        maintenance = cleaned_data.get("maintenance")

        if (not check_diagnosis) and (not repair) and (not install) and (not maintenance):
            self.add_error(None, "At least one modality option must be checked.")
        else:
            return cleaned_data

字符串
check_diagnostic、repair、install和maintenance字段是布尔字段。
这里的观点：

def post(self, request, **kwargs):
    order = Order.objects.get(pk=kwargs['pk'])
    form = self.form_class(request.POST, instance=order)
    ItemTimesFormSet = modelformset_factory(ItemTimes, exclude=['order'])
    formset = ItemTimesFormSet(request.POST)

    if form.is_valid() and formset.is_valid():
        order.items.clear()
        form.save()
        for form in formset:
            if form.cleaned_data.get('item'):
                item = form.cleaned_data.get('item')
                times = form.cleaned_data.get('times')
                ItemTimes.objects.create(
                    order=order,
                    item=item,
                    times=times
                )

        return redirect(self.success_url)

型