anchor.diff:  	    {ok, State}
       end.
   
  +parse_a_values([], _, #state{action=#occi_action{}}=State) ->
  +    {ok, State};
   parse_a_values([], H, #state{entity_id=undefined}=State) ->
       parse_location(H, State);
   parse_a_values([], _, State) ->
  
positive.code: %%%===================================================================
  %%% API
  %%%===================================================================
  parse_action(_Headers, #state{}=_State) ->
      {ok, occi_action:new()}.
  
  parse_entity(Headers, #state{}=State) ->
      case parse_category(Headers, State) of
  
negative.code: 	    {error, Err}
      end.
  
  add_attr(Key, Value, Attrs, H, #state{action=#occi_action{}=A}=S) ->
      try occi_action:set_attr_value(A, Key, Value) of
  	#occi_action{}=A2 ->
  	    parse_a_values(Attrs, H, S#state{action=A2});
  	{error, Err} ->
  	    {error, {parse_error, Err}}
      catch
  	_:Err ->
  	    {error, {parse_error, Err}}
      end;
  add_attr(_, _, _, _, #state{entity=undefined}) ->
      {error, {parse_error, attribute}};
  add_attr(Key, Value, Attrs, H, #state{entity=E}=S) ->
  