prop_insert :: BagTest Int bag => bag Int -> Int -> bag Int -> Bool
prop_insert bag x xs =
    let x_xs = insert x xs
     in si x_xs
        &&
        toOrdList x_xs == List.insert x (toOrdList xs)
prop_insert :: BagTest Int bag => bag Int -> Int -> bag Int -> Bool
prop_insert bag x xs =
    let x_xs = insert x xs
     in si x_xs
        &&
        toOrdList x_xs == List.insert x (toOrdList xs)
prop_insert bag x xs =
    let x_xs = insert x xs
     in si x_xs
        &&
        toOrdList x_xs == List.insert x (toOrdList xs)