HepMC::ShortEventAttribute Node1 HepMC::ShortEventAttribute + NUP + IDPRUP + XWGTUP + SCALUP + AQEDUP + AQCDUP + ShortEventAttribute() + ShortEventAttribute() + from_event() + from_string() + to_string() + resize() Node2 HepMC3::Attribute     Node2->Node1 Node3 std::vector< long > + elements   Node3->Node1 +IDUP Node4 std::vector< int > + elements + elements   Node4->Node1 +ISTUP Node5 std::vector< std::pair < int, int > > + elements + elements   Node5->Node1 +ICOLUP +MOTHUP Node6 std::vector< std::vector < double > > + elements + elements   Node6->Node1 +PUP Node7 std::vector< double > + elements + elements   Node7->Node1 +SPINUP +VTIMUP