oracle simple stored procedure

create or replace
PROCEDURE TESTHM AS
BEGIN
--set serveroutput on;
  --does not work: SELECT SESSIONTIMEZONE, CURRENT_DATE FROM DUAL;
  dbms_output.put_line ('TestHm');
  --does not work: ALTER SESSION SET NLS_DATE_FORMAT = 'DD-MON-YYYY HH24:MI:SS';
  dbms_output.put_line (CURRENT_DATE);
END TESTHM;

testen:
set serveroutput on;      
execute testhm;

mit Parameter:
create or replace

PROCEDURE TESTHM
(
     InTest   IN  VARCHAR2
)
IS
BEGIN
--set serveroutput on;
  dbms_output.put_line ('TestHm Begin');
  dbms_output.put_line (InTest);
END TESTHM;




set serveroutput on;  
execute testhm('Hallo');