def save_form(self, request, form, change):
        r = form.save(commit=False)
        parent_id = request.REQUEST.get('parent_id', None)
        if parent_id:
            parent = Folder.objects.get(id=parent_id)
            r.parent = parent
        return r
Given a ModelForm return an unsaved instance. ``change`` is True if
dataset/ETHPy150Open django-leonardo/django-leonardo/leonardo/module/media/admin/folder/admin.py/FolderAdmin.save_form