+local io = require "io"
+local math = require "math"
+local table = require "table"
+local debug = require "debug"
+local ldebug = require "luci.debug"
+local string = require "string"
+local coroutine = require "coroutine"
+
+local getmetatable, setmetatable = getmetatable, setmetatable
+local rawget, rawset, unpack = rawget, rawset, unpack
+local tostring, type, assert = tostring, type, assert
+local ipairs, pairs, loadstring = ipairs, pairs, loadstring
+local require, pcall, xpcall = require, pcall, xpcall
+local collectgarbage, get_memory_limit = collectgarbage, get_memory_limit
+