How to use the node-opcua-address-space.createExtObjArrayNode function in node-opcua-address-space

function createSubscriptionDiagnosticsArray(this: ServerSession) {
            const subscriptionDiagnosticsArrayType =
            this.addressSpace.findVariableType("SubscriptionDiagnosticsArrayType")!;
          assert(subscriptionDiagnosticsArrayType.nodeId.toString() === "ns=0;i=2171");
  
          this.subscriptionDiagnosticsArray =
            createExtObjArrayNode(this.sessionObject, {
                browseName: { namespaceIndex: 0, name: "SubscriptionDiagnosticsArray" },
                complexVariableType: "SubscriptionDiagnosticsArrayType",
                indexPropertyName: "subscriptionId",
                minimumSamplingInterval: 2000, // 2 seconds
                variableType: "SubscriptionDiagnosticsType",
            });
  
        }
        createSessionDiagnosticSummaryUAObject.call(this);

session._sessionDiagnostics = session.sessionDiagnostics.$extensionObject;
        assert(session._sessionDiagnostics.session === session);

        const sessionDiagnosticsArray = session.getSessionDiagnosticsArray();

        // add sessionDiagnostics into sessionDiagnoticsArray
        eoan.addElement(session._sessionDiagnostics, sessionDiagnosticsArray);

    }

    const subscriptionDiagnosticsArrayType = session.addressSpace.findVariableType("SubscriptionDiagnosticsArrayType");
    assert(subscriptionDiagnosticsArrayType.nodeId.toString() === "ns=0;i=2171");

    session.subscriptionDiagnosticsArray=
        eoan.createExtObjArrayNode(session.sessionObject, {
            browseName: { namespaceIndex: 0,name:"SubscriptionDiagnosticsArray" },
            complexVariableType: "SubscriptionDiagnosticsArrayType",
            variableType: "SubscriptionDiagnosticsType",
            indexPropertyName: "subscriptionId",
            minimumSamplingInterval: 2000 // 2 seconds
        });

    return session.sessionObject;
};