Age Fucntion

Thanks for your time.
 
I'm having some difficulties with the age function.  I need to calculate the difference in days between the current date and a value provided to a function via an argument.  When I try to include my argument in the function, the function won't compile, if I replace my argument with a date value(replace dt_hiredate with '1/1/2007'), it compiles, and the function works as expected.
 
 
my code:
CREATE OR REPLACE FUNCTION "public"."function1" (dt_hiredate TIMESTAMP) RETURNS INTEGER AS
$body$
/* New function body */
DECLARE
BEGIN
    return date_part('year',age(timestamp dt_hiredate))*365 + date_part('day',age(timestamp dt_hiredate));
END;
$body$
LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;
 
Compile message:
ERROR:  syntax error at or near "$1" at character 41
QUERY:  SELECT  date_part('year',age(timestamp  $1 ))*365 + date_part('day',age(timestamp  $2 ))
CONTEXT:  SQL statement in PL/PgSQL function "function1" near line 5

---

View Athletes' Collections with Live Search. See it!