plpgsql : column definition list

The result of the function test() should be a list of integer coming from a
column "ech_id" from a recursive function
data.sp_ech_recurs_desc_a(integer).

I have the following message:
ERROR:  a column definition list is required for functions returning
"record"

How to define this list in this function ?

Thanks
--------
CREATE OR REPLACE FUNCTION test()
  RETURNS SETOF record AS
'
declare
    parent integer;
    rec RECORD;
begin
    ... a "SELECT INTO parent ..." giving a value to the variable parent
...
    FOR rec IN SELECT ech_id from data.sp_ech_recurs_desc_a(parent) LOOP
        RETURN NEXT rec;
    END LOOP;
return;
end
'
  LANGUAGE 'plpgsql' VOLATILE;
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