How can a double tap be detected?

I've tried multiple scenarios. What I am trying to do is allow a basic function to fire when You double tap "A", but I can't seem to do it. I assume the problem is that input2 is already being set as "A" when I first press it because pressing it for the second time in the game means that every time you press it hence it will fire the function.

bool = true
locplay = game.Players.LocalPlayer
human = locplay.Character.Humanoid
game:GetService("UserInputService").InputBegan:connect(function(input1)
	if input1.KeyCode == Enum.KeyCode.A then
	local bool = false
		wait(.02)
		if bool == false then
			game:GetService("UserInputService").InputBegan:connect(function(input2)
				if input2.KeyCode == Enum.KeyCode.A then
				local bool = true
					if bool == true then
						human.WalkSpeed = 50
						wait(.25)
						human.WalkSpeed = 16
					end
				end
			end)
		end
	end
end)
bool = false