I have deployed https://github.com/aws-samples/amazon-elasticsearch-service-with-cognito to my stack, and am trying to add a master group as per https://docs.aws.amazon.com/elasticsearch-service/latest/developerguide/fgac.html#fgac-walkthrough-iam

So I have added to the following https://github.com/aws-samples/amazon-elasticsearch-service-with-cognito/blob/master/lib/search-stack.ts#L50

diff --git a/lib/search-stack.ts b/lib/search-stack.ts
index 85de0c0..2493c92 100644
--- a/lib/search-stack.ts
+++ b/lib/search-stack.ts
@@ -3,7 +3,7 @@

 import { Fn, Stack, Construct, StackProps, CfnParameter, CfnOutput } from '@aws-cdk/core';
 import { CfnDomain } from '@aws-cdk/aws-elasticsearch';
-import { UserPoolAttribute, CfnUserPoolDomain, CfnIdentityPool, CfnIdentityPoolRoleAttachment, CfnUserPool } from '@aws-cdk/aws-cognito';
+import { UserPoolAttribute, CfnUserPoolDomain, CfnIdentityPool, CfnIdentityPoolRoleAttachment, CfnUserPool, CfnUserPoolGroup } from '@aws-cdk/aws-cognito';
 import { Role, ManagedPolicy, ServicePrincipal, FederatedPrincipal } from '@aws-cdk/aws-iam';
 import { CustomResource } from '@aws-cdk/aws-cloudformation';

@@ -55,6 +55,19 @@ export class SearchStack extends Stack {
       }, "sts:AssumeRoleWithWebIdentity")
     });

+    // create two groups, one for admins one for users
+
+    new CfnUserPoolGroup(this, "AdminsGroup", {
+      groupName: "master-user-group",
+      userPoolId: idPool.ref,
+
+    });
+
+    new CfnUserPoolGroup(this, "UsersGroup", {
+      groupName: "limited-user-group",
+      userPoolId: idPool.ref,
+    });
+
     const esRole = new Role(this, "esRole", {
       assumedBy: new ServicePrincipal('es.amazonaws.com'),
       managedPolicies: [ManagedPolicy.fromAwsManagedPolicyName("AmazonESCognitoAccess")]
~

but after redeploying the roles are not being created!

any advice is much appreciated.