code: def init_logging(logger, log_file, log_level):
    
    with open(log_file, 'w'):
      pass
    numeric_level = getattr(logging, log_level.upper(), None) if log_level else logging.INFO
    if not isinstance(numeric_level, int):
      raise ValueError('Invalid log level: %s' % log_level)
    logger.setLevel(logging.DEBUG)
    fh = logging.FileHandler(log_file)
    fh.setLevel(logging.DEBUG)
    ch = logging.StreamHandler()
    ch.setLevel(numeric_level)
    formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
    fh.setFormatter(formatter)
    ch.setFormatter(formatter)
    logger.addHandler(fh)
    logger.addHandler(ch)
    return CONSTANTS.OK
docs: Initialize the naarad logger.
    :param: logger: logger object to initialize
    :param: log_file: log file name
    :param: log_level: log level (debug, info, warn, error)