anchor.diff:          checkNonNull "list1" list1
           checkNonNull "list2" list2
   
  -        lzy <| fun () ->
  +        LazyList<_>.CreateLazy <| fun () ->
               match list1.Value, list2.Value with
               | Cons (hd1, tl1), Cons (hd2, tl2) ->
                   consCell (mapping hd1 hd2) (map2 mapping tl1 tl2)
  
positive.code:         // Preconditions
          checkNonNull "list" list
  
          lzy <| fun () ->
              match list.Value with
              | Empty ->
                  Empty
  
negative.code:         // TODO :   Right now, we're evaluating the entire sequence, then wrapping the results in a LazyList.
          //          It would be more efficient to evaluate the sequence on-demand, though we need to decide if it's safe enough.
          //          Or, we could use type tests on 'sequence' so if it's an array, list, etc., we can use a more-efficient conversion to LazyList.
          // LazyList.collect f (LazyList.ofSeq sequence)
          LazyList.collect f (LazyList.ofList (List.ofSeq sequence))
      member __.Bind (lazyValue : Lazy<'T>, binding : 'T -> LazyList<'U>) =
          LazyList.Delayed (fun () ->
  