code: public CfgParseChart parseMarginal(List<?> terminals, boolean useSumProduct) {
      Factor rootDist = TableFactor.unity(parentVar);
      return parseMarginal(terminals, rootDist, useSumProduct);
    }
docs: Computes the marginal distribution over CFG parses given terminals.
  
  @param terminals
  @param useSumProduct
  @return