"attempt to index nil with 'Position'" - Error?

Hi, am making a NPC turret that seraches for players then walks to them and kill them but am facing an error wich is the same as the title. Here is the code:

local myHuman = script.Parent:WaitForChild("Humanoid")
local myRoot = script.Parent:WaitForChild("HumanoidRootPart")
local myHead = script.Parent:WaitForChild("Head")
local headWeld = myHead:WaitForChild("HeadWeld")
local tip = script.Parent:WaitForChild("Tip")
local flash = tip:WaitForChild("Flash")

local myTeam = script.Parent:WaitForChild("Team")

--sounds
local shootSound = myHead:WaitForChild("Shoot")
local chargeSound = myHead:WaitForChild("Charge")

local clone = script.Parent:Clone()

local gunCool = true
local maxCharge = 10
local charges = maxCharge
local home = myRoot.Position

-- Error happens here
function checkDist (target)
	return (myRoot.Position - target.Position).Magnitude	
end

and here I defind the target :

function findTarget ()
	local dist = 100
	local target = nil
	for i,v in ipairs(workspace:GetChildren()) do
		local human = v:FindFirstChild("Humanoid")
		local torso = v:FindFirstChild("Torso") or v:FindFirstChild("HumanoidRootPart")
		local team = v:FindFirstChild("Team")
		if human and torso then
			if checkDist(target) < dist and human.Health > 0 then
				if team then
					if team.Value ~= myTeam.Value then
						dist = checkDist(target)
						target = torso
					end
				else
					dist = checkDist(target)
					target = torso
				end
			end
		end
	end
	return target
end

Any help is appreiciated !

Anyways, thank you so much guys for who read this post I already figured the issue !!

function findTarget ()
	local dist = 100
	local target = nil
	for i,v in ipairs(workspace:GetChildren()) do
		local human = v:FindFirstChild("Humanoid")
		local torso = v:FindFirstChild("Torso") or v:FindFirstChild("HumanoidRootPart")
		local team = v:FindFirstChild("Team")
		if human and torso then
			if checkDist(torso) < dist and human.Health > 0 then
				if team then
					if team.Value ~= myTeam.Value then
						dist = checkDist(torso)
						target = torso
					end
				else
					dist = checkDist(torso)
					target = torso
				end
			end
		end
	end
	return target
end

hey you! have you ever heard of enes? if you are in trouble, better call enes!