code: public double getTagSequenceProb() {
      // System.err.println("Parse.getTagSequenceProb: "+type+" "+this);
      if (this.parts.size() == 1
          && this.parts.get(0).type.equals(ShiftReduceParser.TOK_NODE)) {
        // System.err.println(this+" "+prob);
        return Math.log(this.prob);
      } else if (this.parts.size() == 0) {
        System.err.println("Parse.getTagSequenceProb: Wrong base case!");
        return 0.0;
      } else {
        double sum = 0.0;
        for (final Parse parse : this.parts) {
          sum += parse.getTagSequenceProb();
        }
        return sum;
      }
    }
docs: Returns the probability associated with the pos-tag sequence assigned to
  this parse.
  
  @return The probability associated with the pos-tag sequence assigned to
  this parse.