docs: private InstanceSet readInstanceSet(String pos) throws IOException {
  
  		InstanceSet instset = new InstanceSet();
  
  		LabelAlphabet labelAlphabet = factory.buildLabelAlphabet(pos);
  
  		BufferedReader in = new BufferedReader(new InputStreamReader(
  				new FileInputStream(fp), charset));
  
  		String line = null;
  		while ((line = in.readLine()) != null) {
  			line = line.trim();
  			if (line.matches("^$"))
  				continue;
  			if (line.startsWith(pos + " ")) {
  				List<String> tokens = Arrays.asList(line.split("\\s+"));
  
  				int[] data = new int[tokens.size() - 2];
  				for (int i = 0; i < data.length; i++) {
  					data[i] = Integer.parseInt(tokens.get(i + 2));
  				}
  				Instance inst = new Instance(data);
  				inst.setTarget(labelAlphabet.lookupIndex(tokens.get(1)));
  
  				instset.add(inst);
  			}
  		}
  
  		in.close();
  
  		labelAlphabet.setStopIncrement(true);
  		instset.setAlphabetFactory(factory);
  
  		return instset;
  	}