// Set Operation: Union
 public void unionWith(DataSet otherDataSet)
 {
     this.egoNetworkList.UnionWith(otherDataSet.egoNetworkList);
 }
        /************************** Secondary Methods ******************************/
        public Tuple<DataSet, DataSet> getTrainTestSet(int index)
        {
            DataSet trainSet = new DataSet();
            DataSet testSet = dataSets[index]; // TestSet Setting

            for (int i = 0; i < this.dataSets.Length; i++)
            {
                if (i != index)
                    trainSet.unionWith(dataSets[i]);
            }

            return new Tuple<DataSet, DataSet>((DataSet)trainSet, (DataSet)testSet);
        }