code: public AlignedExpressionTree getBestAlignment(AlignmentExample example) {
      CfgParser parser = getCfgParser(example);
      ExpressionTree tree = example.getTree();
      
      Factor rootFactor = getRootFactor(tree, parser.getParentVariable());
      CfgParseChart chart = parser.parseMarginal(example.getWords(), rootFactor, false);
      CfgParseTree parseTree = chart.getBestParseTree();
  
      return decodeCfgParse(parseTree, 0);
    }
docs: Get the highest-scoring logical form derivation for {@code example}
  according to this model.
  
  @param example
  @return