[Haskell-cafe] Std lib equivalent for liftM concat . sequence

A couple of days ago I had need for:

concatM :: Monad m => [m [a]] -> m [a] concatM = liftM concat . sequence

but found no such thing in the std libs, except perhaps for msum (I don't want to add instances for MonadPlus. Should I have to?). Have I missed something trivial? Alistair