Flask BuildError，无法为终结点生成url

Question

我有以下几点url_for

url_for('posts.post_images', filename=post.img, size=710)

以及路线的方法

@posts.route('/posts/images/<path:filename>/<int:size>')
def post_images(filename, size):
    if size:
        return ImageProcessingService.get_image_by_size(filename, size)
    path = os.path.join(os.getcwd(), 'src/posts/images')
    return send_from_directory(path, filename)

控制台问我Did you forget to specify values ['size'] 我只是不明白，这两个值都在url_for调用、路由的装饰器和方法的签名中。有什么想法吗

确切的错误是： werkzeug.routing.BuildError: Could not build url for endpoint 'posts.post_images' with values ['filename']. Did you forget to specify values ['size']?