urls.pyapp_name = 'Loader'urlpatterns = [    path('post_detail/', views.Loader_post_view.as_view(), name="post_detail"),    path('post/', views.post.as_view(), name="post"),    path('my_job/', views.Loader_post_list.as_view(), name="my_job"),    path('delete/<int:pk>', views.Loader_post_delete.as_view(), name="Delete"),    path('update/<int:pk>', views.Loader_post_update.as_view(template_name="post_detail.html"),     name="Update")] 這是我 models.pyclass Loader_post(models.Model):    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name="Loader")    pick_up_station = models.CharField(max_length=150)    destination_station = models.CharField(max_length=150)    sender_name = models.CharField(max_length=150)    phone_number = PhoneNumberField(null=False, blank=False, unique=True)    receiver_name = models.CharField(max_length=150)    sending_item = models.CharField(max_length=150)    #image_of_load = models.ImageField(default='',upload_to='static/img')    weight = models.CharField(max_length=150)    metric_unit = models.CharField(max_length=30, default='')    quantity = models.PositiveIntegerField()    pick_up_time = models.DateField()    drop_time = models.DateField()    paid_by = models.CharField(max_length=150)    created_at = models.DateTimeField(auto_now=True)    published_date = models.DateField(blank=True, null=True)def __str__(self):    return self.user.usernamedef get_absolute_url(self):    return reverse("Loader:post", kwargs={'pk': self.pk})如果我的 views.pyclass Loader_post_view(CreateView,LoginRequiredMixin):    form_class = forms.Loader_post_form    model = Loader_post    template_name = "post_detail.html"def form_valid(self, form):    print(form.cleaned_data)    self.object = form.save(commit=False)    self.object.user = self.request.user    self.object.save()    return super().form_valid(form)現在我的問題是，當我點擊提交它顯示錯誤和有時當我把'post'通過替換self，它將工作正常'pk'：self.pk但是，如果新用戶登錄并嘗試發布它不會存儲到數據庫中的數據，請幫助我找出這個錯誤