diff --git a/hedis-pile.cabal b/hedis-pile.cabal
--- a/hedis-pile.cabal
+++ b/hedis-pile.cabal
@@ -1,5 +1,5 @@
 name:           hedis-pile
-version:        0.2.0
+version:        0.2.1
 cabal-version:  >= 1.8
 build-type:     Simple
 stability:      Experimental
diff --git a/src/Database/Redis/Pile.hs b/src/Database/Redis/Pile.hs
--- a/src/Database/Redis/Pile.hs
+++ b/src/Database/Redis/Pile.hs
@@ -63,7 +63,7 @@
             -- ^ Optional expect field.
     -> IO ([(B.ByteString, B.ByteString)], 
            Maybe Integer, 
-           Maybe [B.ByteString])
+           [B.ByteString])
             -- ^ Computation that returns data and 
             --   optional TTL and tags. All tags will be stored as @prefix:tag@.
     -> R.Redis (Maybe [(B.ByteString, B.ByteString)])
@@ -85,11 +85,9 @@
         (r, ke, t) <- liftIO f
         void $ R.hmset withPrefix r
         setExpire ke
-        setTags t
+        RT.markTags [withPrefix] p t
         return $ Just r
       where
         setExpire Nothing = return ()
         setExpire (Just ke) = void $ R.expire withPrefix ke
-        setTags Nothing = return ()
-        setTags (Just ts) = RT.markTags [withPrefix] p ts
         
diff --git a/test/Database/Redis/Test/Pile.hs b/test/Database/Redis/Test/Pile.hs
--- a/test/Database/Redis/Test/Pile.hs
+++ b/test/Database/Redis/Test/Pile.hs
@@ -28,10 +28,10 @@
     teardown
     $ runInRedis $ do
         r <- RP.pile allPrefix "two" Nothing $ 
-            return (allData, Nothing, Nothing)
+            return (allData, Nothing, [])
         liftIO $ Just allData @=? r
         void $ RP.pile allPrefix "three" Nothing $ 
-            return (allData, Just 15, Just ["one"])
+            return (allData, Just 15, ["one"])
         ex <- R.ttl $ allPrefix `B.append` ":three"
         liftIO $ Right 15 @=? ex
 
@@ -41,10 +41,10 @@
     teardown
     $ runInRedis $ do
         r <- RP.pile allPrefix "one" Nothing $ 
-            return (allData, Nothing, Nothing)
+            return (allData, Nothing, [])
         liftIO $ Just allData @=? r
         r' <- RP.pile allPrefix "one" (Just ("etag", "etag")) $ 
-            return (allData, Nothing, Nothing)
+            return (allData, Nothing, [])
         liftIO $ Nothing @=? r'
 
 runInRedis :: forall b. R.Redis b -> IO b