anchor.diff:      rc([Dict:rec2msg(element(1, Rec))], RC, Dict).
   
   %% failed_avp/3
  +
  +failed_avp(_, [] = No, _) ->
  +    No;
   
   failed_avp(Msg, [_|_] = Avps, Dict) ->
       [failed(Msg, [{'AVP', Avps}], Dict)].
  
positive.code: 
  %% reset/4
  %%
  %% Set Result-Code and/or Failed-AVP (maybe).
  
  reset(Msg, [], _) ->
      Msg;
  
  reset(Msg, [{RC, Avp}], Dict) ->
      set(Msg, rc(Msg, RC, Dict) ++ failed_avp(Msg, [Avp], Dict), Dict);
  
  reset(Msg, [RC], Dict) ->
      set(Msg, rc(Msg, RC, Dict), Dict).
  
  %% set/3
  
  
negative.code: %% select_error/3
  %%
  %% Extract the first appropriate RC or {RC, #diameter_avp{}}
  %% pair from an errors list, along with any leading #diameter_avp{}.
  %%
  %% RFC 6733:
  %%
  