src/log4php/Logger.php
public static function getHierarchy() {
		if(!isset(self::$hierarchy)) {
			self::$hierarchy = new LoggerHierarchy(new LoggerRoot());
		}
		return self::$hierarchy;
	}
public static function getHierarchy() {
		if(!isset(self::$hierarchy)) {
			self::$hierarchy = new LoggerHierarchy(new LoggerRoot());
		}
		return self::$hierarchy;
	}
Returns the hierarchy used by this Logger.

Caution: do not use this hierarchy unless you have called initialize().
To get Loggers, use the Logger::getLogger and Logger::getRootLogger
methods instead of operating on on the hierarchy directly.

@return LoggerHierarchy