postresql dmy() function

create or replace function dmy( p_day int, p_month int, p_year int)
returns date
language plpgsql
as $$
declare
   ret_dmy date;
begin
  SELECT TO_DATE(p_year::varchar||LPAD(p_month::varchar, 2, '0')||p_day::varchar,'YYYYMMDD')
  into ret_dmy;
  return ret_dmy;
end;$$