anchor.diff:  		      EncodedValue, "</value></member>"],
   	    encode_members(Rest, NewAcc)
       end;
  -encode_members([{Name, Value}|Rest], Acc) -> {error, {invalid_name, Name}};
  +encode_members([{Name, _Value}|_Rest], _Acc) -> {error, {invalid_name, Name}};
   encode_members(UnknownMember, Acc) ->
       {error, {unknown_member, UnknownMember}}.
   
  
positive.code: 	    NewAcc = Acc++["<value>", EncodedValue, "</value>"],
  	    encode_values(Rest, NewAcc)
      end;
  encode_values([{Name, Value}|Rest], Acc) -> {error, {invalid_name, Name}};
  encode_values(UnknownMember, Acc) ->
      {error, {unknown_member, UnknownMember}}.
  
negative.code: 	    {ok, EncodedPayload};
  	no -> {error, {bad_string, String}}
      end;
  payload({response, []}) ->
      {ok, ["<?xml version=\"1.0\"?><methodResponse></methodResponse>"]};
  payload({response, [Param]}) ->
      case encode_params([Param]) of
  	{error, Reason} -> {error, Reason};
  	EncodedParam ->
  