Why is the touched:connect function getting called with nil?

Here's my module

I get a "rightFoot" "here1" and "nil" when the touch happens. The first function is called properly from another checkpoint script.

Here's the call:

local playerDataManager = require(workspace.PlayerDataManager)

local deadBoard = script.Parent
deadBoard.Touched:connect(function(hit)
	print (hit)
	playerDataManager.moveToLastCheckpoint(hit)
end) 

And here's the module:

local PlayerDataManager = {}

local DataStoreService = game:GetService("DataStoreService")
local playersDataStore = DataStoreService:GetDataStore("PlayerData")


local sessionData = Instance.new("Model")
sessionData.Name = "SessionData"

local players = game:GetService("Players")

function PlayerDataManager:recordCheckpoint(hit,checkpointPart)
	print(hit)
	if hit and hit.Parent and hit.Parent:FindFirstChild("Humanoid") then
		local player = players:GetPlayerFromCharacter(hit.Parent)
		
		local playerData = sessionData:FindFirstChild(tostring(player.userId))
		--local checkpoint = checkpointData:FindFirstChild(tostring(player.userId))
		
		if not playerData then
			playerData = Instance.new("Model", sessionData)
			playerData.Name = tostring(player.userId)
			
			player.CharacterAdded:connect(function(character)
				wait()
				character:WaitForChild("HumanoidRootPart").CFrame =  game.ServerStorage.CheckpointData[tostring(player.userId)].Value.CFrame * CFrame.Angles(0, 0, math.rad(-90)) + Vector3.new(0, 10, 0)
			end)
		end
		
		local lastCheckpoint = playerData:FindFirstChild("LastCheckpoint")
		if not lastCheckpoint then
			lastCheckpoint = Instance.new("ObjectValue", playerData)
			lastCheckpoint.Name = "LastCheckpoint"
		end
		
		lastCheckpoint.Value = checkpointPart
		print(sessionData:FindFirstChild(tostring(player.userId)))
	end
end

function PlayerDataManager:moveToLastCheckpoint(hit)
	print("here1")
	print(hit)
	if hit and hit.Parent and hit.Parent:FindFirstChild("Humanoid") then
		local player = players:GetPlayerFromCharacter(hit.Parent)
		print("here2")
		local playerData = sessionData:FindFirstChild(tostring(player.userId))
		if playerData then
			print(playerData)
			local lastCheckpoint = playerData:FindFirstChild("LastCheckpoint")
			if lastCheckpoint then
				print(lastCheckpoint)
				player.character:WaitForChild("HumanoidRootPart").CFrame =  lastCheckpoint.Value.CFrame * CFrame.Angles(0, 0, math.rad(-90)) + Vector3.new(0, 10, 0)
			end
		end
		
	end
end

return PlayerDataManager

Nevermind. &*$!ing colons. Seriously, why colons?

Need to change line 6 from

playerDataManager.moveToLastCheckpoint(hit)

to

playerDataManager:moveToLastCheckpoint(hit)