def addNewPost(self, post):
        # Why even let posts manage their own ids?  Oh well.
        assert post.id == self.next_id,\
               (post.id, self.next_id) % "Bad post ID; is %r, should be %r"
        self.posts.append(post)
        self.next_id += 1
dataset/ETHPy150Open twisted/nevow/examples/blogengine/axiomstore.py/Blog.addNewPost/swapped operands of `%`