foldl1 :: (a  ->  a  ->  a)  ->  (List a)  ->  a;
foldl1 f (Cons x xs) = foldl f x xs
foldl1 :: (a  ->  a  ->  a)  ->  (List a)  ->  a
foldl1 f (Cons x xs) = foldl f x xs
foldl1 f (Cons x xs) = foldl f x xs