code: public void functionScore(OperatorCall<GroupCQ> queryLambda, ScoreFunctionCall<ScoreFunctionCreator<GroupCQ>> functionsLambda,
              final ConditionOptionCall<FunctionScoreQueryBuilder> opLambda) {
          GroupCQ cq = new GroupCQ();
          queryLambda.callback(cq);
          final Collection<FilterFunctionBuilder> list = new ArrayList<>();
          if (functionsLambda != null) {
              functionsLambda.callback((cqLambda, scoreFunctionBuilder) -> {
                  GroupCQ cf = new GroupCQ();
                  cqLambda.callback(cf);
                  list.add(new FilterFunctionBuilder(cf.getQuery(), scoreFunctionBuilder));
              });
          }
          final FunctionScoreQueryBuilder builder = regFunctionScoreQ(cq.getQuery(), list);
          if (opLambda != null) {
              opLambda.callback(builder);
          }
      }
docs: =============