anchor.diff:  
   -record(state, { monitoring }).
   -define(SERVER, ?MODULE).
  +-define(TAB, etorrent_piece_tbl).
   -ignore_xref([{'start_link', 0}]).
   %%====================================================================
   %% API
  
positive.code: find_interest_piece(_Id, none, Acc) ->
      {interested, Acc};
  find_interest_piece(Id, {Pn, Next}, Acc) ->
      case ets:lookup(etorrent_piece_tbl, {Id, Pn}) of
          [] ->
              invalid_piece;
          [#piece{ state = State}] ->
  
negative.code: %% Description: Is the piece interesting?
  %%--------------------------------------------------------------------
  interesting(Id, Pn) when is_integer(Id) ->
      [P] = ets:lookup(?TAB, {Id, Pn}),
      P#piece.state =/= fetched.
  
  %% Search an iterator for a not_fetched piece. Return the #piece
  