run data pump out of procedure (DBMS_DATAPUMP)

1. create directory
create directory clone_auto as '';
2. create user
create user dba_clone_user identified by test123;
grant connect, create database link, resource, create view to dba_clone_user;
grant unlimited tablespace to dba_clone_user;
grant exp_full_database to dba_clone_user;
grant read,write on directory clone_auto to dba_clone_user;
grant execute on dbms_flashback to dba_clone_user;
grant create table to dba_clone_user;
grant FLASHBACK ANY TABLE to dba_clone_user;

2. create procedure
CREATE OR REPLACE PROCEDURE dba_clone_user.start_export
IS
   hdl_job        NUMBER;
   l_cur_scn      NUMBER;
   l_job_state    VARCHAR2 (20);
   l_status       SYS.ku$_status1010;
   l_job_status   SYS.ku$_jobstatus1010;
BEGIN
   
   begin
    execute immediate 'drop table  DBA_CLONE_USER.AUTO_EXPORT';
   exception when others then null;
   end;
   
   hdl_job := DBMS_DATAPUMP.OPEN ( operation => 'EXPORT', job_mode => 'SCHEMA', job_name => 'AUTO_EXPORT');
   dbms_datapump.set_parameter(hdl_job, 'FLASHBACK_SCN', dbms_flashback.get_system_change_number);
   dbms_datapump.set_parameter(hdl_job, 'COMPRESSION', 'METADATA_ONLY');
   dbms_datapump.metadata_filter (handle => hdl_job, name => 'SCHEMA_LIST', value => '''USER1''');
   dbms_datapump.set_parallel(hdl_job, 5);
  
   DBMS_DATAPUMP.add_file (handle => hdl_job,
                           filename => 'user1%U.dmp',
                           directory => 'CLONE_AUTO',
                           --filesize   IN VARCHAR2 DEFAULT NULL,
                           filetype => DBMS_DATAPUMP.ku$_file_type_dump_file,
                           reusefile => 1
                          );
                         
   DBMS_DATAPUMP.add_file (handle => hdl_job,
                           filename => 'auto_export.log',
                           DIRECTORY => 'CLONE_AUTO',
                           --filesize   IN VARCHAR2 DEFAULT NULL,
                           filetype => DBMS_DATAPUMP.ku$_file_type_log_file,
                           reusefile => 1
                          );
                         
   DBMS_DATAPUMP.start_job (handle => hdl_job);
  
   DBMS_DATAPUMP.wait_for_job (handle => hdl_job, job_state => l_job_state);
  
   DBMS_OUTPUT.put_line ('Job exited with status:' || l_job_state);
  
END;
/