yl_template/setup.lua

local function run_once()
    local dl = minetest.get_dir_list(yl_template.worldpath, true)
    local create = true

    for _, v in ipairs(dl) do
        if v == yl_template.settings.save_path then
            create = false
        end
    end

    if create then
        minetest.mkdir(yl_template.worldpath .. DIR_DELIM .. yl_template.settings.save_path)
    end
end

run_once()