Method execute

include/pybind11/detail/init.h:350–359

              enable_if_t<Class::has_alias && std::is_constructible<Alias<Class>, Args...>::value,
                          int> = 0>
    static void execute(Class &cl, const Extra &...extra) {
        cl.def(
            "__init__",
            [](value_and_holder &v_h, Args... args) {
                v_h.value_ptr()
                    = construct_or_initialize<Alias<Class>>(std::forward<Args>(args)...);
            },
            is_new_style_constructor(),
            extra...);
    }
};

// Implementation class for py::init(Func) and py::init(Func, AliasFunc)