Small fixes and tests.

diff --git a/Network/YAML/Base.hs b/Network/YAML/Base.hs
index 3c82805..2a3c416 100644
--- a/Network/YAML/Base.hs
+++ b/Network/YAML/Base.hs
@@ -70,6 +70,5 @@ unserialize :: IsYamlObject a => BS.ByteString -> Maybe a
 unserialize x =
   let d :: Maybe YamlObject
       d = decode x
-  in  case d of
-        Just y -> Just $ cs y
-        Nothing -> Nothing
+  in  cs `fmap` d
+
diff --git a/Test.hs b/Test.hs
index 1421dbd..35cd10a 100644
--- a/Test.hs
+++ b/Test.hs
@@ -18,8 +18,18 @@ double (Point x y) = return $ Point (x*2) (y*2)
 mySum :: [Double] -> IO Double
 mySum = return . sum

+counter :: Int -> IO Int
+counter k = do
+    mapM count [k..k+10]
+    return (k+10)
+  where
+    count i = do
+      print i
+      threadDelay 1000000
+
 rules = mkRules [("double", yamlMethod double),
-                 ("sum",    yamlMethod mySum)]
+                 ("sum",    yamlMethod mySum),
+                 ("count",  yamlMethod counter)]

 main = do
   putStrLn "Listening..."
diff --git a/TestCall.hs b/TestCall.hs
index b21aeda..5a1a1fb 100644
--- a/TestCall.hs
+++ b/TestCall.hs
@@ -28,3 +28,5 @@ main = do
   print (s :: Double)
   rs <- callP getService "test" "double" ps
   print (rs :: [Point])
+  cs <- callP getService "test" "count" ([3,4,5,6] :: [Int])
+  print (cs :: [Int])
diff --git a/yaml-rpc.cabal b/yaml-rpc.cabal
index 710a2de..e8a08a2 100644
--- a/yaml-rpc.cabal
+++ b/yaml-rpc.cabal
@@ -43,7 +43,7 @@ Build-type:          Simple
 -- Extra-source-files:

 -- Constraint on the version of Cabal needed to build this package.
-Cabal-version:       >=1.2
+Cabal-version:       >=1.4


 Library
@@ -57,7 +57,7 @@ Library

   -- Packages needed in order to build this package.
   Build-depends:       yaml, data-object-yaml, network, template-haskell, bytestring,
-                       data-object, data-default, base, mtl, convertible-text,
+                       data-object, data-default, base >= 3 && <= 5, mtl, convertible-text,
                        containers

   -- Modules not exported by this package.