我是python的初学者，django编码。我得到了一个网页，任务是允许使用表单保存数据。但我似乎无法在清理后取出数据。清洗后似乎没有任何价值。
以下是我的代码：在forms.py中

class DeviceDetailForm(ModelForm):
    class Meta:
        model= DeviceDetail
        fields= '__all__'
    def clean(self):
        cleaned_data = super(DeviceDetailForm, self).clean()
        hostname = cleaned_data.get('hostname')
        if len(hostname) < 8:
            raise forms.ValidationError('Hostname needs to be more than 8 character long, ' + hostname )

in views.py

def device_add(request):
    if request.method == "POST":
        device_frm = DeviceForm(request.POST)
        if device_frm.is_valid():
            new_device = device_frm.save()
            devices = Device.objects.all()
            return render(request, 'interface/device_display.html',{'devices':devices})
        dd_frm = DeviceDetailForm(request.POST)
        di_frm = DeviceInterfaceForm(request.POST)

        if dd_frm.is_valid() and di_frm.is_valid():
            if dd_frm.is_valid():
                dd_frm.save()
                devicedetail = dd_frm.save(commit=False)
                devicedetail.save()
                dd_frm.save_m2m()

                deviceinterface = di_frm.save(commit=False)
                deviceinterface.hostname = devicedetail.hostname
                deviceinterface.save()
    else:
        device_frm = DeviceForm
        return render(request, 'interface/device_add.html',{'form':device_frm} )
        dd_frm = DeviceDetailForm()
        di_frm = DeviceInterfaceForm()
    context = {'dd_frm':dd_frm, 'di_frm':di_frm, 'title':'Device Add'}
    return render(request, 'interface/device_add.html',context)

在models.py中

class DeviceDetail(models.Model):
    hostname = models.CharField(max_length=50)
    mgt_interface = models.CharField(max_length=50)
    mgt_ip_addr = models.CharField(max_length=30)
    subnetmask = models.CharField(max_length=30)
    ssh_id = models.CharField(max_length=50)
    ssh_pwd = models.CharField(max_length=50)
    enable_secret = models.CharField(max_length=50)
    device_model = models.CharField(max_length=50)