user:/AddOns/sidTools/StartUp.lua:48: Cannot find a library instance of "LibSlashCommander".
stack traceback:
	user:/AddOns/sidTools/lib/LibStub/LibStub.lua:29: in function 'LibStub:GetLibrary'
	user:/AddOns/sidTools/StartUp.lua:48: in function 'callback'
	user:/AddOns/sidTools/StartUp.lua:23: in function '(anonymous)'

SLASH_COMMANDS["/lang"] = function(args)
    SetCVar("language.2", zo_strtrim(args))
end

local tmp_args = {}
 
local function arglist(...)
    local n = select("#", ...)
    for i = 1, n do
        local a = select(i, ...)
        if type(a) == "string" then
            tinsert(tmp_args, strformat("%q", a))
        else
            tinsert(tmp_args, tostring(a))
        end
    end
    return tconcat(tmp_args, ", ", 1, n)
end

local function FindAddonsMatchingPattern(...)
    local npat = select("#", ...)
    local out = {}
    for index = 1, AddOnManager:GetNumAddOns() do
        local name = AddOnManager:GetAddOnInfo(index)
        for j = 1, npat do
            local pat = select(j, ...)
            local ms, me = strfind(name, pat)
            if ms == 1 and me == #name then
                out[#out + 1] = index
                break
            end
        end
    end
    return out                                              
end
 
function AddonIsolator:IsolateAddons(addonPatterns)
    local addonIndices = FindAddonsMatchingPattern(zo_strsplit(" ", addonPatterns))
    ...
end