public static bool CanAppendToLinkChart( 
   Map linkChart,
   KnowledgeGraphLayerIDSet idSet
)

//We create an id set to contain the records to be appended
var dict = new Dictionary<string, List<long>>();
dict["Suspects"] = new List<long>(); 

//In this case, via results from a query...
var qry2 = "MATCH (s:Suspects) RETURN s";

QueuedTask.Run(async () =>
{
  using (var kg = kg_layer.GetDatastore())
  {
    var graphQuery = new KnowledgeGraphQueryFilter()
    {
      QueryText = qry2
    };

    using (var kgRowCursor = kg.SubmitQuery(graphQuery))
    {
      while (await kgRowCursor.WaitForRowsAsync())
      {
        while (kgRowCursor.MoveNext())
        {
          using (var graphRow = kgRowCursor.Current)
          {
            var obj_val = graphRow[0] as KnowledgeGraphNamedObjectValue;
            var oid = (long)obj_val.GetObjectID();
            dict["Suspects"].Add(oid);
          }
        }
      }
    }

    //make an ID Set to append to the LinkChart
    var idSet = KnowledgeGraphLayerIDSet.FromDictionary(kg, dict);
    //Get the relevant link chart to which records will be
    //appended...in this case, from an open map pane in the
    //Pro application...
    var mapPanes = FrameworkApplication.Panes.OfType<IMapPane>().ToList();
    var mapPane = mapPanes.First(
      mp => mp.MapView.IsLinkChartView && 
      mp.MapView.Map.Name == "Acme Link Chart");
    var linkChartMap = mapPane.MapView.Map;

    //or get the link chart from an item in the catalog...etc.,etc.
    //var projectItem = Project.Current.GetItems<MapProjectItem>()
    //      .FirstOrDefault(pi => pi.Name == "Acme Link Chart");
    //var linkChartMap = projectItem?.GetMap();

    //Call AppendToLinkChart with the id set
    if (linkChartMap.CanAppendToLinkChart(idSet))
      linkChartMap.AppendToLinkChart(idSet);
  }
});