<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def worker_stop(obj, worker_ids):
 """ Stop running workers. \b WORKER_IDS: The IDs of the worker that should be stopped or none to stop them all. """

    if len(worker_ids) == 0:
        msg = 'Would you like to stop all workers?'
    else:
        msg = '\n{}\n\n{}'.format('\n'.join(worker_ids),
                                  'Would you like to stop these workers?')

    if click.confirm(msg, default=True, abort=True):
        stop_worker(obj['config'],
                    worker_ids=list(worker_ids) if len(worker_ids) > 0 else None)