prop_null xs i = runner1 (enumPure1Chunk xs =<< enumPure1Chunk [] i)
                 == runner1 (enumPure1Chunk xs i)
  where types = (xs :: [Int], i :: I)
prop_null xs i = runner1 (enumPure1Chunk xs =<< enumPure1Chunk [] i)
                 == runner1 (enumPure1Chunk xs i)
  where types = (xs :: [Int], i :: I)
prop_null xs i = runner1 (enumPure1Chunk xs =<< enumPure1Chunk [] i)
                 == runner1 (enumPure1Chunk xs i)
  where types = (xs :: [Int], i :: I)