Postgres outputting an array in PSQL

I have the following function. It is something I am building and want to show the contents of stuff_list so I can prove it is working correctly. I can’t however work out what output type I should be using:

CREATE OR REPLACE FUNCTION isf.update_tbl_variadic(VARIADIC _stuff_array stuff[])   RETURNS SETOF BIGINT[]   LANGUAGE plpgsql AS $  $   DECLARE     stuff_list BIGINT[]; BEGIN          stuff_list:= ARRAY (         SELECT id     FROM stuff As s     WHERE s."id"     IN (     SELECT t.id     FROM unnest(_stuff_array) as t(        id,        x,        y,        created    )))  FOR UPDATE;      RAISE NOTICE '%', stuff_list;     RETURN stuff_list; END; $  $  ; 

Is anyone able to help me with this please? I need to generate an array from this to be used in a subsequent query, but for now I just need to see the output.

Many thanks