eqv [a@(List xs), b@(List ys)] = listEquals (\x y -> eqv [x, y]) a b
eqv [a@(List xs), b@(List ys)] = listEquals (\x y -> eqv [x, y]) a b
eqv [a@(List xs), b@(List ys)] = listEquals (\x y -> eqv [x, y]) a b