-- >>> catMaybes [Just 1, Nothing, Just 2]
    -- [1, 2]
    -- >>> catMaybes [Nothing, Nothing, Nothing]
    -- []
    catMaybes :: [Maybe a] -> [a]
    catMaybes list = map M.fromJust (filter isJust list)
catMaybes :: [Maybe a] -> [a]
catMaybes list = map M.fromJust (filter isJust list)
catMaybes list = map M.fromJust (filter isJust list)