We now have

       return std::reduce(x.begin(), x.end());

Which is a little cleaner and is even faster (compiler is free to do the additions in any order). https://en.cppreference.com/w/cpp/algorithm/reduce - it looks like even the `accumulate` example can be made simpler with `std::plus`. I prefer the `reduce` option for a number of reasons, but understand why someone might not.