How to stop DataPump Job 2

DECLARE
  n NUMBER:=0;
  errm VARCHAR2(2000);
BEGIN
FOR i IN (SELECT job_name, owner_name FROM dba_datapump_jobs ) LOOP
  n := DBMS_DATAPUMP.ATTACH( JOB_NAME => i.job_name, JOB_OWNER => i.owner_name );
  DBMS_OUTPUT.PUT_LINE( n );
  DBMS_DATAPUMP.STOP_JOB( n );
END LOOP;
EXCEPTION
WHEN OTHERS THEN
 BEGIN
      errm := SQLERRM;
   DBMS_OUTPUT.PUT_LINE( errm );
 END;
END;
/