diff --git a/README.md b/README.md
index 9d5254a..47ae77f 100644
--- a/README.md
+++ b/README.md
@@ -40,9 +40,10 @@ mymod.speed_monoid = player_monoids.make_monoid({
 	end,
 	fold = function(tab)
 		local res = 1
-	     	for _, speed in pairs(tab) do
+		for _, speed in pairs(tab) do
 			res = res * speed
-	     	end
+		end
+		return res
 	end,
 	identity = 1,
 	apply = function(speed, player)
@@ -108,9 +109,10 @@ newmod.speed_boosts = player_monoids.make_monoid({
 	end,
 	fold = function(tab)
 		local res = 1
-	     	for _, speed in pairs(tab) do
+		for _, speed in pairs(tab) do
 			res = math.max(res, speed)
-	     	end
+		end
+		return res
 	end,
 	identity = 1,
 	apply = ???
@@ -202,4 +204,4 @@ global state.
 * The order that different effects get combined together is based on key order,
 which may not be predictable. So you should try to make your monoids commutative
 in addition to associative, or at least not care if the order of two changes
-is swapped.
\ No newline at end of file
+is swapped.