prop_nullH xs = P.length xs > 0 ==>
                runner1 (enumPure1Chunk xs =<< enumPure1Chunk [] Iter.head)
                == runner1 (enumPure1Chunk xs Iter.head)
  where types = xs :: [Int]
prop_nullH xs = P.length xs > 0 ==>
                runner1 (enumPure1Chunk xs =<< enumPure1Chunk [] Iter.head)
                == runner1 (enumPure1Chunk xs Iter.head)
  where types = xs :: [Int]
prop_nullH xs = P.length xs > 0 ==>
                runner1 (enumPure1Chunk xs =<< enumPure1Chunk [] Iter.head)
                == runner1 (enumPure1Chunk xs Iter.head)
  where types = xs :: [Int]