prop_interval :: (Random a, Ord a) => a -> a -> Property
prop_interval a b = do
  c <- choose (a,b)
  property (c `member` (interval a b))
prop_interval :: (Random a, Ord a) => a -> a -> Property
prop_interval a b = do
  c <- choose (a,b)
  property (c `member` (interval a b))
prop_interval a b = do
  c <- choose (a,b)
  property (c `member` (interval a b))