*/
class PropertyHolder { // DO NOT DERIVE THIS CLASS, or the diamond inheritance mayhem will get you
std::unique_ptr<std::unordered_map<std::string, std::string>> properties_ = nullptr;
*/
class PropertyHolder { // DO NOT DERIVE THIS CLASS, or the diamond inheritance mayhem will get you
std::unique_ptr<std::unordered_map<std::string, std::string>> properties_ = nullptr;