public Dictionary<MapMember,List<long>> ToDictionary()

{
  // Loads the selected features into an Inspector instance.
  // get the first layer and its corresponding selected feature OIDs
  var firstSelectionSet = selectedFeatures.ToDictionary().First();
  // create an instance of the inspector class
  var inspector = new Inspector();
  // load the selected features into the inspector using a list of object IDs
  await inspector.LoadAsync(firstSelectionSet.Key, firstSelectionSet.Value);
}

// Retrieves the value of a specific attribute and the geometry of the first selected feature from the provided selection set.
await QueuedTask.Run(() =>
{
  // get the first layer and its corresponding selected feature OIDs
  var firstSelectionSet = selectedFeatures.ToDictionary().First();

  // create an instance of the inspector class
  var inspector = new Inspector();

  // load the selected features into the inspector using a list of object IDs
  inspector.Load(firstSelectionSet.Key, firstSelectionSet.Value);

  //get the value of
  var pscode = inspector["STATE_NAME"];
  var myGeometry = inspector.Shape;
});

{
  await QueuedTask.Run(() =>
  {
    MapMemberIDSet rootNodes = MapView.Active.GetRootNodes();
    var rootNodeDict = rootNodes.ToDictionary();

    // rootNodeDict is a Dictionary<MapMember, List<long>>

    // access a particular mapMember in the Dictionary
    if (rootNodeDict.ContainsKey(mapMember))
    {
      var oids = rootNodeDict[mapMember];
    }

    // OR iterate through the dictionary
    foreach (var (mm, oids) in rootNodeDict)
    {
      // do something
    }
  });
}