def handle_worker(args):
    """usage: {program} worker [options] <module-path> <operator> <occurrence> [<config-file>]

    Run a worker process which performs a single mutation and test run.
    Each worker does a minimal, isolated chunk of work: it mutates the
    <occurence>-th instance of <operator> in <module-path>, runs the test
    suite defined in the configuration, prints the results, and exits.

    Normally you won't run this directly. Rather, it will be launched
    by an execution engine. However, it can be useful to run this on
    its own for testing and debugging purposes.

    options:
      --keep-stdout             Do not squelch stdout

    """
    config = load_config(args.get('<config-file>'))

    with open(os.devnull, 'w') as devnull:
        with redirect_stdout(sys.stdout if args['--keep-stdout'] else devnull):
            work_item = cosmic_ray.worker.worker(
                Path(args['<module-path>']),
                config.python_version, args['<operator>'],
                int(args['<occurrence>']),
                config.test_command,
                None)

    sys.stdout.write(json.dumps(work_item, cls=WorkItemJsonEncoder))

    return ExitCode.OK
usage: {program} worker [options] <module-path> <operator> <occurrence> [<config-file>]

    Run a worker process which performs a single mutation and test run.
    Each worker does a minimal, isolated chunk of work: it mutates the
    <occurence>-th instance of <operator> in <module-path>, runs the test
    suite defined in the configuration, prints the results, and exits.

    Normally you won't run this directly. Rather, it will be launched
    by an execution engine. However, it can be useful to run this on
    its own for testing and debugging purposes.

    options:
      --keep-stdout             Do not squelch stdout