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;
	}
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
Returns the hierarchy used by this Logger .