Set the logging level for the "can" logger.
    Expects one of: 'critical', 'error', 'warning', 'info', 'debug', 'subdebug'

def set_logging_level(level_name=None):
    """Set the logging level for the "can" logger.
    Expects one of: 'critical', 'error', 'warning', 'info', 'debug', 'subdebug'
    """
    can_logger = logging.getLogger('can')

    try:
        can_logger.setLevel(getattr(logging, level_name.upper()))
    except AttributeError:
        can_logger.setLevel(logging.DEBUG)
    log.debug("Logging set to {}".format(level_name))