public Autodesk.Revit.UI.Result Execute(Autodesk.Revit.UI.ExternalCommandData commandData,
                                               ref string message,
                                               ElementSet elements)
        {
            if (null == commandData.Application.ActiveUIDocument.Document)
            {
                message = "Active document is null.";
                return Result.Failed;
            }

            try
            {
                var creator = new FamilyInstanceCreator(commandData.Application);

                var importer = new PSDataImporter(creator);

                importer.StartImport();

                return Autodesk.Revit.UI.Result.Succeeded;
            }
            catch (Exception ex)
            {
                message = ex.Message;
                return Autodesk.Revit.UI.Result.Failed;
            }
        }
 public PSDataImporter(FamilyInstanceCreator creator)
 {
     this._creator = creator;
 }