How can you clone using TextButtons?

Hey guys, and thank you very much for helping me out a little while ago (Whomever you were). Now, while I was building, I caught a problem that I could not figure out how to solve. How would you clone a tool named "Sword" in Lighting into a player's Backpack when the player clicks on a Gui TextButton? The following script is placed inside the TextButton, but it will not work. Again if you can, please help me. Thank you VERY much for spending your time to correct my errors.

function mouseclick(player)
	if player.Backpack:FindFirstChild("Sword") then
		script.Parent.Text = "Already owned"
		wait(1)
		script.Parent.Text = "1000 $"
		else
		game.Lighting.Uzi:Clone().Parent = player.Backpack
		script.Parent.Text = "BOUGHT"
		wait(1)
		script.Parent.Text = "1000 $"
	end
end
script.Parent.MouseButton1Down:connect(mouseclick)