Sprint script is not functioning properly?

the script is popping up in output with ServerScriptService.Sprint:2: attempt to indext local 'Player' (a nil value)

local Player = game.Players.LocalPlayer
local Mouse = Player.GetMouse()
local KeysDown = {}

Mouse.KeyDown:connect(function(Key)
	if Key:lower() == "w" then
		KeysDown["w"] = true
	elseif Key:byte() == 48 then
		KeysDown["Shift"] = true
	end
	
	if KeysDown["w"] and KeysDown["Shift"] then
		Player.Character.Humanoid.WalkSpeed = 32
	end
end)

Mouse.KeyUp:connect(function(Key)
	if Key:Lower() == "w" then
		KeysDown["w"] = false
	elseif Key:byte() == 48 then
		KeysDown["Shift"] = false
	end
	
	if not KeysDown["w"] or not KeysDown["Shift"] then
		Player.Character.Humanoid.WalkSpeed = 16
	end
end)