def set_stream_logger(log_level=logging.DEBUG, format_string=None, logger_name='smc'): 
    """ 
    Stream logger convenience function to log to console
    
    :param int log_level: A log level as specified in the `logging` module
    :param str format_string: Optional format string as specified in the 
        `logging` module
    """ 
    if format_string is None: 
        format_string = LOG_FORMAT
 
    logger = logging.getLogger(logger_name) 
    logger.setLevel(log_level)
    
    # create console handler and set level
    ch = logging.StreamHandler() 
    ch.setLevel(log_level)
    # create formatter
    formatter = logging.Formatter(format_string)
    # add formatter to ch
    ch.setFormatter(formatter) 
    logger.addHandler(ch)