如何合并std::tuple内部的std::unordered_map？

#include <tuple>
#include <unordered_map>

// 合并std::tuple内部的std::unordered_map
template <typename... Maps>
std::unordered_map<typename Maps::key_type, typename Maps::mapped_type> mergeMaps(const std::tuple<Maps...>& maps) {
    std::unordered_map<typename Maps::key_type, typename Maps::mapped_type> mergedMap;
    mergeMapsHelper(maps, mergedMap, std::index_sequence_for<Maps...>());
    return mergedMap;
}

// 辅助函数，递归合并std::unordered_map
template <typename... Maps, std::size_t... Is>
void mergeMapsHelper(const std::tuple<Maps...>& maps, std::unordered_map<typename Maps::key_type, typename Maps::mapped_type>& mergedMap, std::index_sequence<Is...>) {
    ((mergedMap.insert(std::begin(std::get<Is>(maps)), std::end(std::get<Is>(maps)))), ...);
}

int main() {
    std::unordered_map<int, std::string> map1{{1, "one"}, {2, "two"}};
    std::unordered_map<int, std::string> map2{{3, "three"}, {4, "four"}};
    std::unordered_map<int, std::string> map3{{5, "five"}, {6, "six"}};

    std::tuple<std::unordered_map<int, std::string>, std::unordered_map<int, std::string>, std::unordered_map<int, std::string>> maps{map1, map2, map3};

    std::unordered_map<int, std::string> mergedMap = mergeMaps(maps);

    // 输出合并后的std::unordered_map
    for (const auto& pair : mergedMap) {
        std::cout << pair.first << ": " << pair.second << std::endl;
    }

    return 0;
}

1: one
2: two
3: three
4: four
5: five
6: six