postgres event trigger and function not working

i looked for a event trigger which fired up after creation of a table. I found some good posts here and do some test. My problem is that nothing happens, no errors nor output. So please give some advice what i do wrong. Here my code. I'am complete new in postgres, come from oracle, so please forgive me for this maybe "simple" question.

create table createt (tname char(20));

CREATE OR REPLACE FUNCTION insert()
RETURNS event_trigger
AS $$
DECLARE r RECORD;
BEGIN
r := pg_event_trigger_ddl_commands();
INSERT INTO createt VALUES(r.object_identity);
END;
$$
LANGUAGE plpgsql;

CREATE EVENT TRIGGER insert_event ON ddl_command_end
WHEN TAG IN ('CREATE TABLE')
EXECUTE PROCEDURE insert();

So in this testcase i want to put the tablename of the newly createt table in the table createt! But nothing happens. How can i check if the trigger is fired up. Or how can i debug the function?

Thanks for your time and advices.

The function pg_event_trigger_ddl_commands() returns set of rows. The trigger function must be ready to accept more than a single row, e.g.:

CREATE OR REPLACE FUNCTION insert()
RETURNS event_trigger
AS $$
BEGIN
    INSERT INTO createt 
    SELECT object_identity
    FROM pg_event_trigger_ddl_commands();
END;
$$
LANGUAGE plpgsql;

char(20) is not enough for object_identity, use text:

DROP TABLE createt;
CREATE TABLE createt (tname text);

What happens when you create a table with serial primary key?

create table my_table(id serial primary key);

Let's check:

select *
from createt

         tname          
------------------------
 public.my_table_id_seq
 public.my_table
 public.my_table_pkey
 public.my_table_id_seq
(4 rows)    

There are two actions on the sequence, first to crete it and the other to set owned by with alter sequence.