Pass kwargs from CreateView to ModelForm?

I am trying to pass kwarg from CreateView to ModelForm so that I can dynamically adjust the fields based on the values ​​in the corresponding Parent object. Other answers indicated that passing kwarg by overriding get_form_kwargs on the view and the trick with kwarg.pop on the form should work, but I get an AttributeError: "ChildForm" has no "get" attribute when I try. Passing kwarg to the view context works, but doesn't give me access to the value inside the form instance.

models.py:

class Parent(models.Model):
    name = models.CharField(max_length=255)
    details = models.CharField(max_length=255)
    detailstwo = models.CharField(max_length=255, null=True)
    child_mod = models.BooleanField(default=False)
    slug = models.SlugField()
    creator = models.ForeignKey(User)

    def save(self, *args, **kwargs):
        if not self.id:
            self.slug = slugify(self.name)
        super(Parent, self).save(*args, **kwargs)

    def __str__(self):
        return self.name


class Child(models.Model):
    parent = models.ForeignKey(Parent)
    parent_mod = models.CharField(max_length=255)
    child_name = models.CharField(max_length=255)

    def __unicode__(self):
        return self.child_name

      

        
        
        
      

    

views.py:

class ChildCreateView(CreateView):
    model = Child
    form_class = ChildForm
    template_name = 'testapp/child_form.html'

    def dispatch(self, *args, **kwargs):
        return super(ChildCreateView, self).dispatch(*args, **kwargs)

    def get_form_kwargs(self, **kwargs):
        kwargs = super(ChildCreateView, self).get_form_kwargs()
        parent = get_object_or_404(Parent, slug=self.kwargs['parent_slug'])
        kwargs['parent'] = parent
        return kwargs

    def get_context_data(self, **kwargs):
        context = super(ChildCreateView, self).get_context_data(**kwargs)
        parent = get_object_or_404(Parent, slug=self.kwargs['parent_slug'])
        context['parent'] = parent
        return context

    def form_valid(self, form):
        child = form.save(commit=False)
        parent_slug = form.data['parent_slug']
        parent = get_object_or_404(Parent, slug=parent_slug)
        child.parent = parent
        return super(ChildCreateView, self).form_valid(form)

    def get_success_url(self):
        return reverse('testapp:parent_view', kwargs={'slug': self.object.parent.slug})

      

        
        
        
      

    

forms.py:

class ChildForm(forms.ModelForm):

    class Meta:
        model = Child
        fields = ['parent', 'parent_mod', 'child_name']

    def __init__(self, *args, **kwargs):
        self.parent_object = kwargs.pop('parent')
        assert isinstance(self.parent_object, Parent)
        super(ChildForm, self).__init__(self, *args, **kwargs)
        self.fields["parent_slug"] = forms.CharField(widget=forms.HiddenInput())

        if not self.parent_object.child_mod:
            del self.fields['parent_mod']

      

        
        
        
      

    

The full Traceback is here: http://dpaste.com/2QBMRJX