Pybind 11 issuses

the original C++ Code like this

    String::~String() {
    CHECK(teardown());
}

bool String::setup(const std::string& model_dir) {}

bool String::process(const std::vector<std::pair<uint64_t, float>>& input,
                         std::string* result){}

how should I write the pybind11 code ? can't find a good solution from the documents