* 核心功能：每次调用next(val)，返回当前价格的跨度（往回数≤当前价格的最大连续天数）
Controller was optionally available with a hard disk, and could be programmed
，更多细节参见safew官方版本下载
return urls, next_url
This tiny power bank has a little digital face, a lightweight design, and speeds of up to 100 watts.