anchor.diff:      //
       let toArray (tree : CharDiet) =
           // Preconditions
  -        assert (dietInvariant tree)
  -        assert (intervalsDisjoint tree)
  +//        assert (dietInvariant tree)
  +//        assert (intervalsDisjoint tree)
   
           let elements = ResizeArray ()
           iter elements.Add tree
  
positive.code:     /// Returns a new set with the elements of the second set removed from the first.
      let difference (input : CharDiet) (stream : CharDiet) : CharDiet =
          // Preconditions
          assert (dietInvariant input)
          assert (dietInvariant stream)
          assert (intervalsDisjoint input)
          assert (intervalsDisjoint stream)
  
          match input, stream with
          | Empty, _ ->
  
negative.code:     static member ToSet (charSet : CharSet) : Set<char> =
          // Preconditions
          checkNonNull "charSet" charSet
          //assert (CharDiet.dietInvariant charSet.Tree)
          //assert (CharDiet.intervalsDisjoint charSet.Tree)
  
          CharDiet.toSet charSet.Tree
  
  