esta dando esse erro quando tento adicionar um item no shop
[Error - TalkAction Interface]
2023-01-23 05:18:10 - data/talkactions/scripts/shop.lua:onSay
2023-01-23 05:18:10 - Description:
2023-01-23 05:18:10 - data/talkactions/scripts/shop.lua:2: attempt to call global 'isNumeric' (a nil value)
2023-01-23 05:18:10 - stack traceback:
2023-01-23 05:18:10 - data/talkactions/scripts/shop.lua:2: in function <data/talkactions/scripts/shop.lua:1>