code: @BetaApi
    public final AggregatedListInstanceGroupManagersPagedResponse aggregatedListInstanceGroupManagers(
        String project) {
      AggregatedListInstanceGroupManagersHttpRequest request =
          AggregatedListInstanceGroupManagersHttpRequest.newBuilder().setProject(project).build();
      return aggregatedListInstanceGroupManagers(request);
    }
docs: Retrieves the list of managed instance groups and groups them by zone.
  
  <p>Sample code:
  
  <pre><code>
  try (InstanceGroupManagerClient instanceGroupManagerClient = InstanceGroupManagerClient.create()) {
  ProjectName project = ProjectName.of("[PROJECT]");
  for (InstanceGroupManagersScopedList element : instanceGroupManagerClient.aggregatedListInstanceGroupManagers(project.toString()).iterateAll()) {
  // doThingsWith(element);
  }
  }
  </code></pre>
  
  @param project Project ID for this request.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails