inheritance of functions

In Postgres Users Guide, CREATE TABLE section, the following is stated:
Postgres automatically allows the created table to inherit functions on
tables above it in the inheritance hierarchy. 
         Aside: Inheritance of functions is done according to the
conventions of the Common Lisp Object System (CLOS). 

I have tried different constructs but I have not been able to create such a
functions. Can anybody send me an example of a function that will be
inherited by inherited table? I. e.
create table A (
.
.
);

create function F ...

create table B (
..
) inherits (A);

Now I assume that I can somehow use function F on table B 

Thank you, 
Regards,
Andrzej Mazurkiewicz