code: func NewPerceptronTagger() *PerceptronTagger {
  	var wts map[string]map[string]float64
  	var tags map[string]string
  	var classes []string
  
  	dec := model.GetAsset("classes.gob")
  	util.CheckError(dec.Decode(&classes))
  
  	dec = model.GetAsset("tags.gob")
  	util.CheckError(dec.Decode(&tags))
  
  	dec = model.GetAsset("weights.gob")
  	util.CheckError(dec.Decode(&wts))
  
  	return &PerceptronTagger{model: NewAveragedPerceptron(wts, tags, classes)}
  }
docs: // NewPerceptronTagger creates a new PerceptronTagger and loads the built-in
  // AveragedPerceptron model.