Oracle to Postgres : create type as object in Postgres

Hello,

I've a Oracle type that I must translate to Postgres. This Oracle type is like below :

CREATE OR REPLACE
type D_Temp_Element as object
(
   MEMBER FUNCTION to_string return Varchar2,
   MEMBER FUNCTION duration return D_Interval,
   ...
) ;

How can I do that in Postgres ? Is there something that be equivalent ?
Thanks.

Rachid