Hi everyone, Sorry if this email disturbs you. I haven't used a developer's mailing list before so I'm not sure if I'm violating any etiquette. If I do, please excuse me. I'm trying to understand the type of sequence [Just, Just]. I can understand sequence [Just 1, Just 2] :: Num a => Maybe [a] because when looking at the type of sequence sequence :: (Monad m, Traversable t) => t (m a) -> m (t a) it is clear that this function takes a collection of monadic values and return a single monadic value of the collection. Thus, when we call sequence [Just 1, Just 2] we should get back a Just of [1,2]. Following that train of thoughts, shouldn't sequence [Just, Just] return a single Just? Here is the corresponding SO question http://stackoverflow.com/questions/34244574/trouble-understanding-the-type-o... Lim