Function base_class_check_key

extlibs/sol3/include/sol/sol.hpp:7900–7903

	namespace detail {

		inline decltype(auto) base_class_check_key() {
			static const auto& key = "class_check";
			return key;
		}

		inline decltype(auto) base_class_cast_key() {
			static const auto& key = "class_cast";