How can this code not work!?

Hello, I tried to make a method function for workspace to make a part in and put in "()" its name. What is wrong? It asks me in line 6 for an object literally for no reason I can think of.

** Workspace.Script:6: bad argument #3 to 'Workspace' (Object expected, got table)**

game.Workspace = {
	MakePart = function(n)
		local a = Instance.new("Part", game.Workspace)
		a.Name = n
	end
}
game.Workspace:MakePart("Explantation, anyone?")

Try this:

function MakePart(n)
local a = Instance.new("Part", workspace)
a.Name = n
end
MakePart("This Should Work!")