docs: public void trainOnInstanceImpl(MultiLabelInstance inst) {
  		if (inst.weight() > 0) {
  			checkRoot();
  
  			double[] prediction = treeRoot.getPrediction(inst);
  			double[] normalError = getNormalizedError(inst, prediction);
  			//normalError.scaleValues(inst.weight());
  			processInstance(inst, treeRoot, prediction, normalError, true, false);
  
  			examplesSeen += inst.weight();
  			for (int i = 0; i < inst.numberOutputTargets(); i++) {
  				sumOfValues.addToValue(i, inst.weight() * inst.valueOutputAttribute(i));
  				sumOfSquares.addToValue(i, inst.weight() * inst.valueOutputAttribute(i) * inst.valueOutputAttribute(i));
  			}
  
  			for (int i = 0; i < inst.numInputAttributes(); i++) {
  				sumOfAttrValues.addToValue(i, inst.weight() * inst.valueInputAttribute(i));
  				sumOfAttrSquares.addToValue(i, inst.weight() * inst.valueInputAttribute(i) * inst.valueInputAttribute(i));
  			}
  		}
  	}