def patch_default_retcodes():
    """
    Sets the default luigi return codes in ``luigi.retcodes.retcode`` to:

        - already_running: 10
        - missing_data: 20
        - not_run: 30
        - task_failed: 40
        - scheduling_error: 50
        - unhandled_exception: 60
    """
    import luigi.retcodes

    retcode = luigi.retcodes.retcode

    retcode.already_running._default = 10
    retcode.missing_data._default = 20
    retcode.not_run._default = 30
    retcode.task_failed._default = 40
    retcode.scheduling_error._default = 50
    retcode.unhandled_exception._default = 60