anchor.diff:          List.rev resultList1,
           List.rev resultList2
   
  -/// Returns the number of list elements matching a given predicate.
  -// List.countWith predicate list = (List.filter predicate list |> List.length)
  +/// <summary>Returns the number of list elements matching a given predicate.</summary>
  +/// <param name="predicate"></param>
  +/// <param name="list"></param>
  +/// <returns></returns>
  +/// <remarks>
  +/// This function is an optimized implementation of: <c>List.filter predicate list |> List.length</c>
  +/// </remarks>
   [<CompiledName("CountWith")>]
   let countWith (predicate : 'T -> bool) (list : 'T list) : int64 =
       // Preconditions
  
positive.code:     | el :: set ->
          el = value || contains value set
  
  /// Returns the last element of a list.
  [<CompiledName("Last")>]
  let rec last (list : 'T list) =
      match list with
  
negative.code:         // Return the final state value
          state
  
  /// <summary>
  /// Applies a function to each element of the collection and the element which
  /// proceeds it, threading an accumulator argument through the computation.
  /// </summary>
  /// <param name="folder"></param>
  /// <param name="list"></param>
  /// <param name="state"></param>
  /// <returns></returns>
  [<CompiledName("FoldBackPairwise")>]
  let foldBackPairwise (folder : 'T -> 'T -> 'State -> 'State) list state =
      // Preconditions
  