def launch_celery_workers(spec, steps=None, worker_args='',
    just_return_command=False):
    """
    Launch celery workers for the specified MerlinStudy.

    spec                MerlinSpec object
    steps               The steps in the spec to tie the workers to
    worker_args         Optional celery arguments for the workers
    just_return_command Don't execute, just return the command
    """
    queues = spec.make_queue_string(steps)
    worker_command = ' '.join(['celery worker -A merlin', worker_args, '-Q',
        queues])
    if just_return_command:
        return worker_command
    else:
        pass
