I'm working on a gun script, and when I click, the output says "Argument 2 missing or nil", and clicking on it brings me to line 21. Here's the script:

-- Variables
 
local UserInputService = game:GetService("UserInputService")

local player = game.Players.LocalPlayer
local mouse = player:GetMouse()

local tool = script.Parent

local equipped = false
-- Raycasting Function

local function semiFire()
	local camera = workspace.CurrentCamera
	
	local semiParams = RaycastParams.new()
	semiParams.FilterDescendantsInstances = {} 
	semiParams.FilterType = Enum.RaycastFilterType.Blacklist
	
	local function semiResult(x, y)
	    local unitRay = camera:ScreenPointToRay(x, y)
	    return workspace:Raycast(unitRay.Origin, unitRay.Direction * 500, semiParams)
	end
	
	local semiResultV = semiResult()
	
	if semiResultV then
		local hitPart = semiResultV.Instance
		local humanoid = hitPart.Parent:FindFirstChild("Humanoid")
		if not humanoid then
			local humanoid = hitPart.Parent.Parent:FindFirstChild("Humanoid")
		end
		if not humanoid then end
		if humanoid then 
			print("THERES A HUMANOID POGGERS WOWOWOWOWOW")
		end
	end
end
-- Equip / Unequip

tool.Equipped:Connect(function(mouse)
	equipped = true
end)

tool.Unequipped:Connect(function(mouse)
	equipped = false
end)

-- Firing


UserInputService.InputBegan:Connect(function(input)
	if equipped == true then
		if input.UserInputType == Enum.UserInputType.MouseButton1 then
			semiFire()
		end
	end
end)


UserInputService.InputEnded:Connect(function(input)
	if equipped == true then
		if input.UserInputType == Enum.UserInputType.MouseButton1 then
			
		end
	end
end)

Any help is much appreciated.

Anonymous