anchor.diff:    return _pathRegExp.hasMatch(s);
   }
   
  -final _logger = new Logger('observe.PathObserver');
  +final Logger _logger = new Logger('observe.PathObserver');
  
positive.code:   }
  
    if (_logger.isLoggable(Level.FINER)) {
      _logger.log("can't set $property in $object");
    }
    return false;
  }
  
negative.code:   }
  
    if (_logger.isLoggable(Level.FINER)) {
      _logger.finer("can't get $property in $object");
    }
    return null;
  }
  