SubgroupSvc Node1 SubgroupSvc - m_subgroup - m_mustBeNew + SubgroupSvc() + ~SubgroupSvc() + initialize() + group() Node2 extends< AthService, IH5GroupSvc >     Node2->Node1 Node3 ServiceHandle< IH5GroupSvc >     Node3->Node1 -m_parent Node4 std::unique_ptr< H5 ::Group > + ptr + operator->() Node4->Node1 -m_group