def METHOD_NAME(self):
    form = PageUpdateForm(
        instance=self.flatpage_1,
        data={"title": "test", "url": "/new/url/", "content": "my content here"},
    )
    form.save()
    self.flatpage_1.refresh_from_db()
    page = self.flatpage_1
    self.assertEqual(page.title, "test")
    self.assertEqual(page.url, "/new/url/")
    self.assertEqual(page.content, "my content here")