Keydown to a Enum.KeyCode. function? [EDITED]

Shift to run

Code is not working

local Player = game.Players.LocalPlayer
local Mouse = Player:GetMouse()
local UserInputService = game:GetService('UserInputService')



UserInputService.InputBegan:Connect(function(input)



if  input.KeyCode == Enum.KeyCode.W then
Enum.KeyCode.W  = true
elseif Key:byte() == 48 then
Enum.KeyCode.LeftShift = true
end

if  input.KeyCode == Enum.KeyCode.LeftShift then
Player.Character.Humanoid.WalkSpeed = 38
end
end)


UserInputService.InputBegan:Connect(function(input)

if input.KeyCode == Enum.KeyCode.W then
input.KeyCode = Enum.KeyCode.W == false
elseif Key:byte() == 48 then
input.KeyCode = Enum.KeyCode.LeftShift == false
end

if not input.KeyCode == Enum.KeyCode.W or not input.KeyCode == Enum.KeyCode. LeftShift then
Player.Character.Humanoid.WalkSpeed = 16
end
end)