return function (title, cats, lang_code)
local lang = require("Module:languages").getByCode(lang_code)
if not lang then
return "This module has an invalid language code in the title: <code>" .. lang_code .. "</code>."
end
cats:insert(lang:getCanonicalName() .. " data modules|affix")
return "This module contains data for affixes in "
.. lang:makeCategoryLink()
.. " that is used by <code>{{[[Template:affix|af]]|"
.. lang_code
.. "|...}}</code>. <code>affix_mappings</code> determines which page to link to when certain affixes are used."
.. " It maps from the affix supplied to the template to the desired entry to link to,"
.. " or to a table that maps from sense IDs (the value of <code>|id<var>N</var>=</code> or <code>false</code> if there is no sense ID) to desired entries."
end
