calling user defined functions with parameters.. ?

Hi,

I've created a function like this :

CREATE FUNCTION tester(INT4)
RETURNS BOOL AS
'
DECLAREr RECORD;p ALIAS FOR $1;

BEGINSELECT INTO r id_dptFROM dptsWHERE id_dpt=p;
IF NOT FOUND THEN RETURN FALSE;  ELSE
   RETURN TRUE;END IF;
END;
'
LANGUAGE 'plpgsql';

All is ok at creation.
But now , how can i use my function ? i would like a thing like :

SELECT tester(14) AS ok;

But is make a Postgresql parser error

How to do then ??

Thanks for any help or links (other than the postgresql.org website...) !

;)

Regards,

Fred