lua热加载模块

function reloadModule(module_name)    local old_module = package.loaded[module_name] or {}    package.loaded[module_name] = nil    require(module_name)    local new_module = package.loaded[module_name]    for k, v in pairs(new_module) do        old_module[k] = v    end    package.loaded[module_name] = old_module    return old_moduleend