public boolean equivalentWasEndedBys (WasEndedBy description1, WasEndedBy description2) {
        return bothNull (description1, description2)
               || (neitherNull (description1, description2)
                   && equivalentIdentifiers (description1, description2)
                   && equivalentAttributes (description1, description2)
                   && equivalentEventArguments (description1, description2)
                   && equivalentEntities (description1.getTrigger (), description2.getTrigger ())
                   && equivalentActivities (description1.getEnded (), description2.getEnded ())
                   && equivalentActivities (description1.getEnder (), description2.getEnder ()));
    }