someone can help me with this Lua Error? attempt to index local 'items' (a nil value)

the error is the next

1. Item.lua:70: attempt to index local 'items' (a nil value)

2. Item.lua:70: in function Item.lua:66

3. Item.lua:136: in function `CreateMaps'

4. Item.lua:254: in function Item.lua:249 [C]: ?

   66 local function AddMapping(map, key, ...) 67 map[key] = {}; 68 local items = Utils.Pack(...); 69 70 for i = 1, items.n do 71 map[key][items[i]] = true; 72 end 73 end

full file: Item.lua