anchor.diff:          false ->
               error(badarg);
           true ->
  -            PaddingLen = paddinglen(PieceIndex + 1),
  -            <<_:PieceIndex, Status:1, _:PaddingLen, _/binary>> = Elements,
  +            <<_:PieceIndex/bitstring, Status:1, _/bitstring>> = Elements,
               Status > 0
       end.
   
  
positive.code: -spec is_empty(pieceset()) -> boolean().
  is_empty(Pieceset) ->
      #pieceset{size=Size, elements=Elements} = Pieceset,
      <<Memberbits:Size, _/bitstring>> = Elements,
      Memberbits == 0.
  
  %% @doc
  
negative.code:         false ->
              error(badarg);
          true ->
              <<Low:PieceIndex/bitstring, _:1, High/bitstring>> = Elements,
              Updated = <<Low/bitstring, 1:1, High/bitstring>>,
              Pieceset#pieceset{elements=Updated}
      end.
  
  