private IEnumerable <UnpublishMemento> MapUnpublishMemento(Dictionary <FactID, FactID> localIdByRemoteId, UnpublishMemento remoteUnpublish)
        {
            FactID localId;

            if (localIdByRemoteId.TryGetValue(remoteUnpublish.MessageId, out localId))
            {
                yield return(new UnpublishMemento(localId, remoteUnpublish.Role));
            }
        }
 private IEnumerable<UnpublishMemento> MapUnpublishMemento(Dictionary<FactID, FactID> localIdByRemoteId, UnpublishMemento remoteUnpublish)
 {
     FactID localId;
     if (localIdByRemoteId.TryGetValue(remoteUnpublish.MessageId, out localId))
         yield return new UnpublishMemento(localId, remoteUnpublish.Role);
 }