I followed a tutorial (about ordered datastores) but, my code doesn't work! Why doesn't it work?

So, I followed a Tutorial , but my code doesn't work for some reason. (This is my first question on this website and also sorry for bad english) code:

local DataStoreService = game:GetService("DataStoreService")
local PlayerLevelStore = DataStoreService:GetOrderedDataStore("PlayerLevelStore")
-- Put the data in
local PlayerLevels = {
    ["CalledMonk12"] = 61,
    ["SallyWacky"] = 25,
    ["NancyPlays"] = 82,
    ["AwasomeMinecraftYT"] = 11,
    ["Daimian111"] = 111
}
for User, Level in pairs(PlayerLevels) do
    PlayerLevelStore:SetAsync(User, Level)
end
local Pages = PlayerLevelStore:GetSortedAsync(false, 3)
while wait() do
    local Data = Pages:GetCurrentPage()
    for i, v in pairs(Data) do
        print(v.Key)
        print(" - ")
        print(v.Value)
    end
    if Pages.IsFinished() then
        break
    else
        print("---------------------")
        -- Next page
        Pages:AdvanceToNextPageAsync()

    end
end

output:

  nil
  - 
  nil
  nil
   - 
  nil
  nil
   - 
  nil
  04:49:12.055 - ServerScriptService.Script:22: attempt to call a boolean value

More information: Testng style: I use "Run" In roblox studio Script type and location: Script type: Server script Script location: ServerScriptService