Enforce custom permissions for the page instance.

def change_view(self, request, object_id, **kwargs):
        """
        Enforce custom permissions for the page instance.
        """
        page = get_object_or_404(Page, pk=object_id)
        content_model = page.get_content_model()

        kwargs.setdefault("extra_context", {})
        kwargs["extra_context"].update({
            "hide_delete_link": not content_model.can_delete(request),
            "hide_slug_field": content_model.overridden(),
        })

        return super(PageAdmin, self).change_view(request, object_id, **kwargs)