Could you help me with this ModuleScript bug?

Okay, I have been experimenting with ModuleScripts, and I've gotten this bug and I'm not really sure as to how to fix it. I'm attempting to stop speed hackers in my game with this.

ModuleScript(in Workspace):

local g_logic = {}
walkspeed_allowed = false
allowed_walkspeeds = {16}
function g_logic.check_walkspeeds(ws)
    for i,v in pairs(allowed_walkspeeds) do
        if ws == v then
            walkspeed_allowed = true
        end
    end
    if not walkspeed_allowed then
        game.Players.LocalPlayer:Kick()
    end
    walkspeed_allowed = false
end
return g_logic

LocalScript(in StarterGui[this probably isn't the right place for it, but it runs in here.]):

local g_logic = require(game.Workspace.game_logic)
local player = game.Players.LocalPlayer
player.CharacterAdded:connect(function()
    repeat wait() until player.Character.Humanoid
    hum = player.Character.Humanoid
    hum.Changed:connect(function(WalkSpeed)
        g_logic.check_walkspeed(hum.WalkSpeed)
    end)
end)

The error I got was:

Players.Player1.PlayerGui.anti_speed_2:7: attempt to call field 'check_walkspeed' (a nil value)

Thanks for helping.