Keycode is not a valid member of InputObject, help?

I keep getting errors whenever I run this This is a sprinting mechanic btw

local UserInputService = game:GetService("UserInputService")
local player = game.Players.LocalPlayer``
local char = player.Character
KeyPressed = false

UserInputService.InputBegan:Connect(function(input,gameProcessedEvent)
    if input.Keycode == Enum.KeyCode.LeftShift then
        KeyPressed = true
    end
end)

UserInputService.InputEnded:Connect(function(input,gameProcessedEvent)
    if input.Keycode == Enum.KeyCode.LeftShift then
        KeyPressed = false
    end
end)

if KeyPressed == true then
    char.Humanoid.Walkspeed = 32
else
    char.Humanoid.Walkspeed = 16
end

Errors: Players.Flasker917.PlayerScripts.LocalScript:21: attempt to index nil with 'Humanoid' Keycode is not a valid member of InputObject "InputObject"