def METHOD_NAME(load_additional_str):
    tag = Tag(name="tag")
    post0 = Post(id=0, contents="tag post")
    post1 = Post(id=1, contents="no tag post")
    post2 = Post(id=2, contents="tag 2 post")
    tag.save()
    post0.save()
    post1.save()
    post2.save()
    post0.tags.set([tag])
    post2.tags.set([tag])
    Oso.register_constant(tag, "allowed_tag")
    load_additional_str(
        """
        allow(_, _, post: test_app2::Post) if
            allowed_tag in post.tags;
    """
    )
    posts = Post.objects.authorize(None, actor="u", action="r").all()
    assert len(posts) == 2
    assert post0 in posts
    assert post2 in posts