Dba_Jobs Disable Script

I am trying to get a working script that could just go and mark all dba_jobs to BROKEN ==> TRUE
"execute dbms_job.broken(jobno,true)" using a pl/sql script

I have the working structure of the script except for the fact that the goal is not achieved. I came to know that the ALTER SESSION SET CURRENT_SCHEMA does not take effect when used with the DBMS_JOB API.

Is there an alternative I can get this working.

CODE<--------- part of the script : START

FOR l_job_users IN job_users LOOP
execute immediate 'alter session set current_schema='||l_job_users.LOG_USER;
DBMS_OUTPUT.PUT_LINE(current_user);
FOR l_jobs IN jobs(l_job_users.LOG_USER) LOOP
[code].....