code: public Collection<Logger> getParentLoggers() {
  		LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
  		List<Logger> loggers = new ArrayList<>(ctx.getLoggers());
  		Map<String, Logger> parentMap = new HashMap<>();
  		try {
  			for (Logger logger : loggers) {
  				if (null != logger.getParent() && parentMap.get(logger.getParent().getName()) == null) {
  					parentMap.put(logger.getParent().getName(), logger.getParent());
  				}
  			}
  			List<Logger> parents = new ArrayList<>(parentMap.values());
  			Collections.sort(parents, LOGGER_COMP);
  			return parents;
  		} finally {
  			loggers.clear();
  			parentMap.clear();
  		}
  	}
docs: returns all parent loggers
  @return