code: public double getAnomalyScore(Instance inst)
  	{
  		if(this.neighbourhood.size() < 2)
  			return 1.0;
  		
  		Instance nearestNeighbour = getNearestNeighbour(inst, this.neighbourhood, false);
  		Instance nnNearestNeighbour = getNearestNeighbour(nearestNeighbour, this.neighbourhood, true);
  		
  		double indicatorArgument = distance(inst, nearestNeighbour) / distance(nearestNeighbour, nnNearestNeighbour);
  				
  		return indicatorArgument;
  	}
docs: Returns the anomaly score for an argument instance based on the distance from it to its nearest neighbour compared
  to the distance from its nearest neighbour to the neighbour's nearest neighbour.
  
  @param inst the argument instance
  
  @return d(inst, instNN) / d(instNN, instNNNN)