/// <summary>
 /// Adds current graph to VisualResult. If currentResult == null, throws ArgumentNullException.
 /// </summary>
 /// <returns></returns>
 public VisualResultBuilder AddGraphToResult()
 {
     if (currentResult == null)
     {
         throw new ArgumentNullException("Graph is not initialized. Cannot add null value as visual result.");
     }
     else
     {
         visualResult.Graphs.Add(currentResult);
         currentResult = null;
         return this;
     }
 }
 public VisualResultBuilder NewGraph(string title = "")
 {
     currentResult = new VisualResultItem();
     currentResult.Title = title;
     return this;
 }
 /// <summary>
 /// Sets given graph as current graph.
 /// </summary>
 /// <param name="result">Given graph.</param>
 /// <returns></returns>
 public VisualResultBuilder SetCurrentResult(VisualResultItem result)
 {
     currentResult = result;
     return this;
 }