public static IEnumerable <T> GetAllDataObjects <T>(this IBidirectionalGraph <Cluster <T>, ClusterEdge <T> > tree, Cluster <T> cluster)
{
if (tree.IsOutEdgesEmpty(cluster))
{
return(cluster.DataObjects);
}
return(tree.OutEdges(cluster).Aggregate((IEnumerable <T>)cluster.DataObjects, (res, edge) => res.Concat(tree.GetAllDataObjects(edge.Target))));
}