python - ManagementForm 数据丢失或被篡改 Django FormTools Wizard

Question

视图.py

FORMS = [("customer", CustomerModelForm),
         ("supplier", SupplierModelForm),
         ("brand", BrandMasterModelForm)]


TEMPLATES = {"customer": "add_customer.html",
             "supplier": "supplier_master",
             "brand": "add_brand.html"}
        
class MultiStepWizard(SessionWizardView):
    def get_template_names(self):
        return [TEMPLATES[self.steps.current]]

    def done(self, form_list, **kwargs):
        form_data = [form.cleaned_data for form in form_list]
        return render(self.request, "dashboard_inventory.html", {"data":form_data})

网址.py

path('manage_sales/', MultiStepWizard.as_view(FORMS), name="MultiStepWizard")

表格.py

class CustomerModelForm(forms.ModelForm):
    class Meta:
        model = Customer
        fields = ('name','address','contact','email','state','gstin','pan')
        
class SupplierModelForm(forms.ModelForm):
    class Meta:
        model = Supplier
        fields = ('name','address','city','manager','contact')
        widgets = {
            'name':forms.TextInput(attrs={'class': 'form-control'}),
            'address':forms.TextInput(attrs={'class': 'form-control'}),
            'city':forms.TextInput(attrs={'class': 'form-control'}),
            'manager':forms.TextInput(attrs={'class': 'form-control'}),
            'contact':forms.TextInput(attrs={'class': 'form-control'}),
            
            }

class BrandMasterModelForm(forms.ModelForm):
    class Meta:
        model = BrandMaster
        fields=('brand_name', 'suppliername')
        widgets={'brand_name':forms.TextInput(attrs={'class': 'form-control'}),'suppliername':forms.Select(attrs={'id':'choicewa','class': 'form-control','required': 'true'}),

        }

我正在尝试使用 formtool 用我自己的模板保存多步表单。但我收到错误

ManagementForm data is missing or has been tampered Django FormTools Wizard

保存第一个表单时，无法继续进行。