TgcDigit Node1 TgcDigit - m_bcTag + TgcDigit() + TgcDigit() + TgcDigit() + is_valid() + bcTag() Node2 MuonDigit # m_muonId + MuonDigit() + ~MuonDigit() + MuonDigit() + setID() + identify() Node2->Node1 Node3 Identifiable + ~Identifiable() + identify() + identifyHash() + getHelper() Node3->Node2