genTupple :: (Arbitrary a, Arbitrary b) => Gen (a, b)
genTupple = do
  a <- arbitrary
  b <- arbitrary
  return (a, b)
genTupple :: (Arbitrary a, Arbitrary b) => Gen (a, b)
genTupple = do
  a <- arbitrary
  b <- arbitrary
  return (a, b)
genTupple = do
  a <- arbitrary
  b <- arbitrary
  return (a, b)