How to manually load RETURNS SETOF RECORD?

CREATE OR REPLACE FUNCTION PXPORTAL_COMMON_helper.fn_plpgsqltestmulti(
param_subject varchar,
OUT test_id integer,
OUT test_stuff text)
RETURNS SETOF record
AS
$$
BEGIN
_record.test_id[0] := 100;
_record.test_id[1] := 555;
_record.test_stuff[0] := 'cat';
_record.test_stuff[1] := 'cow';
END;
$$
LANGUAGE 'plpgsql' VOLATILE;

*select test_id from PXPORTAL_COMMON_helper.fn_plpgsqltestmulti('123');*
ERROR: subscripted object is not an array
CONTEXT: PL/pgSQL function
pxportal_common_helper.fn_plpgsqltestmulti(character varying) line 3 at
assignment
********** Error **********

ERROR: subscripted object is not an array
SQL state: 42804
Context: PL/pgSQL function
pxportal_common_helper.fn_plpgsqltestmulti(character varying) line 3 at
assignment

*What is the correct way to accomplish this?*
*TIA, Mike*