zengjie

#include <list>
#include <vector>
#include <chrono>
#include <functional>
#include <iostream>

struct Position {
    float x;
    float y;
    void update() {

zengjie

import tornado.web
import tornado.ioloop
import logging
import os.path


def clean_filename(filename):
    i = filename.rfind(".")
    if i != -1:
        filename = filename[0:i] + filename[i:].lower()