innM :: Monad m => TreeF a (m (Tree a)) -> m (Tree a)
innM (PChoiceF    p i     ts) = liftM (PChoice    p i    ) (sequence ts)
innM :: Monad m => TreeF a (m (Tree a)) -> m (Tree a)
innM (PChoiceF    p i     ts) = liftM (PChoice    p i    ) (sequence ts)
innM (PChoiceF    p i     ts) = liftM (PChoice    p i    ) (sequence ts)