public IReadOnlyDictionary<string,KnowledgeGraphEntityType> GetMetaEntityTypes()

//Provenance entity type is stored as a MetaEntityType 
QueuedTask.Run(() =>
{
  //Create a connection properties
  var kg_props =
      new KnowledgeGraphConnectionProperties(new Uri(url));
  using (var kg = new KnowledgeGraph(kg_props))
  {
    //Get the KnowledgeGraph Data Model
    using (var kg_dm = kg.GetDataModel())
    {
      var dict_types = kg_dm.GetMetaEntityTypes();
      //If there is no provenance then MetaEntityTypes will be
      //an empty collection
      foreach (var kvp in dict_types)
      {
        var meta_entity_type = kvp.Value;
        if (meta_entity_type.GetRole() == 
            KnowledgeGraphNamedObjectTypeRole.Provenance)
        {
          //TODO - use the provenance entity type
          var name = meta_entity_type.GetName();

        }
      }
      
    }
  }
});

internal string GetProvenanceEntityTypeName(KnowledgeGraphDataModel kg_dm)
{
  var entity_types = kg_dm.GetMetaEntityTypes();
  foreach (var entity_type in entity_types)
  {
    if (entity_type.Value.GetRole() == KnowledgeGraphNamedObjectTypeRole.Provenance)
      return entity_type.Value.GetName();
  }
  return "";
}
internal bool KnowledgeGraphSupportsProvenance(KnowledgeGraph kg)
{
  //if there is a provenance entity type then the KnowledgeGraph
  //supports provenance
  return !string.IsNullOrEmpty(
    GetProvenanceEntityTypeName(kg.GetDataModel()));
}

internal string GetDocumentEntityTypeName(KnowledgeGraphDataModel kg_dm)
{
  var entity_types = kg_dm.GetEntityTypes();
  foreach (var entity_type in entity_types)
  {
    var role = entity_type.Value.GetRole();
    if (role == KnowledgeGraphNamedObjectTypeRole.Document)
      return entity_type.Value.GetName();
  }
  return "";//Unusual - probably Neo4j user-managed
}

internal bool KnowledgeGraphHasDocumentType(KnowledgeGraph kg)
{
  //uncommon for there not to be a document type
  return !string.IsNullOrEmpty(
    GetDocumentEntityTypeName(kg.GetDataModel()));
}

QueuedTask.Run(() =>
{
  //Create a connection properties
  var kg_props =
      new KnowledgeGraphConnectionProperties(new Uri(url));
  using (var kg = new KnowledgeGraph(kg_props))
  {
    //Get the KnowledgeGraph Data Model
    using (var kg_datamodel = kg.GetDataModel())
    {
      var entities = kg_datamodel.GetEntityTypes();
      var relationships = kg_datamodel.GetRelationshipTypes();
      var provenance = kg_datamodel.GetMetaEntityTypes();

      var all_graph_types = new List<KnowledgeGraphNamedObjectType>();
      all_graph_types.AddRange(entities.Values);
      all_graph_types.AddRange(relationships.Values);
      all_graph_types.AddRange(provenance.Values);

      System.Diagnostics.Debug.WriteLine("\r\nGraph Types");

      int c = 0;
      foreach (var graph_type in all_graph_types)
      {
        var type_name = graph_type.GetName();
        var role = graph_type.GetRole().ToString();

        //equivalent to:
        //var fields = featClassDef.GetFields().Select(f => f.Name).ToList();
        //var field_names = string.Join(",", fields);
        var props = graph_type.GetProperties().Select(p => p.Name).ToList();
        var prop_names = string.Join(",", props);

        System.Diagnostics.Debug.WriteLine($"[{c++}]: " +
            $"{type_name}, {role}, {prop_names}");
      }
    }
  }
});