prop_filter xs n f = n > 0 ==>
 runner2 (enumSpecial xs n (Iter.filter f stream2list)) == P.filter f xs
  where types = xs :: [Int]
prop_filter xs n f = n > 0 ==>
 runner2 (enumSpecial xs n (Iter.filter f stream2list)) == P.filter f xs
  where types = xs :: [Int]
prop_filter xs n f = n > 0 ==>
 runner2 (enumSpecial xs n (Iter.filter f stream2list)) == P.filter f xs
  where types = xs :: [Int]