listToMaybe [] = Nothing
listToMaybe (a:_) = Just a
--- | The 'catMaybes' function takes a list of "Maybe's and returns
+-- | The 'catMaybes' function takes a list of 'Maybe's and returns
-- a list of all the 'Just' values.
catMaybes :: [Maybe a] -> [a]
catMaybes ls = [x | Just x <- ls]