tagValue :: Records -> Maybe (ByteString, ByteString) 
tagValue (Fix (TreeF (U (Record t (B v))) _)) = Just (t,v)
tagValue :: Records -> Maybe (ByteString, ByteString)
tagValue (Fix (TreeF (U (Record t (B v))) _)) = Just (t,v)
tagValue (Fix (TreeF (U (Record t (B v))) _)) = Just (t,v)