Unexpected error after applying sample req transformer plugin

1

I am trying a sample plugin which uses lua lambda expression like this:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
name: request-transformation
plugin: request-transformer
config:
replace:
headers:
- Authorization:$((function()
local value = headers.Authorization
if not value then
return
end
if value:sub(1, 6) == "Basic " then
return value – was already properly formed
end
return "Basic " … value – added proper prefix
end)())

What am I missing?