anchor.diff:  
   
   %% @doc Find if list has a duplicated value
  --spec find_duplicated_terms(list()) ->
  -    false | {true, list()}.
  -
  -find_duplicated_terms(List) ->
  -    case List -- lists:usort(List) of
  -        [] ->
  -            false;
  -        Duplicated ->
  -            {true, Duplicated}
  -    end.
  +-spec find_duplicated(list()) ->
  +    list().
  +
  +find_duplicated(List) ->
  +    List -- lists:usort(List).
   
   
   %% @private
  
positive.code: -spec bjoin(List::[term()], Separator::binary()) -> 
      binary().
  
  bjoin([], _J) ->
      <<>>;
  bjoin([Term], _J) ->
  
negative.code: -export([to_atom/1, to_existing_atom/1, to_ip/1, to_host/1, to_host/2]).
  -export([to_lower/1, to_upper/1, to_capital/1, to_binlist/1, strip/1, unquote/1, is_string/1]).
  -export([bjoin/1, bjoin/2, words/1, capitalize/1, append_max/3, randomize/1]).
  -export([hex/1, extract/2, delete/2, defaults/2, bin_last/2, find_duplicated/1]).
  -export([cancel_timer/1, reply/2, demonitor/1, msg/2]).
  -export([add_id/2, add_id/3]).
  -export([base64_decode/1, base64url_encode/1,  base64url_encode_mime/1, base64url_decode/1]).
  